Friday, 5 December 2025

VFL/AFL Grand Final Day temperatures, 1898-2025

Ever since I studied the 1987 Grand Final in what was then Melbourne’s earliest 30˚C day on record, the relationship between the weather and football has always been on interest to me. The occasional very wet or very hot days are the usual scene of attention, given that the average weather in Melbourne in late September or early October is very pleasant — 17˚C to 19˚C with over 6 hours sunshine each day, or warm enough for a light cotton jumper and jeans, although frequent strong winds make it feel cooler and require warmer clothing.

For this table I have tabulated the maximum temperature in Melbourne on every VFL/AFL Grand Final day since the first was played in 1898, except for 1924 when no grand final was played, and 2020 and 2021 when COVID caused the Grand Final to be played outside Melbourne. The 1948, 1977 and 2010 replays have been included, and weighted equally with the draws when calculating 5-year means. Temperatures have been colour-coded into bands thus:
Temperature band Range
*“Frigid” below -9.4˚C below 15˚F
*“Freezing” -9.4˚C to 0˚C 15˚F to 32˚F
*“Chilly” 0˚C to 7.2˚C 32˚F to 45˚F
“Cold” 7.2˚C to 12.8˚C 45˚F to 55˚F
“Cool” 12.8˚C to 18.3˚C 55˚F to 65˚F
“Comfortable” 18.3˚C to 23.9˚C 65˚F to 75˚F
“Warm” 23.9˚C to 29.4˚C 75˚F to 85˚F
“Hot” 29.4˚C to 35˚C 85˚F to 95˚F
*“Sweltering” above 35˚C above 95˚F
* = not found in Grand Final Day sample

VFL/AFL Grand Final Day Maximum Temperatures (Second Games are Replays)

For this table, because the Bureau of Meteorology is reluctant to trust temperature data before 1910 — unfortunate given that the 1900s were globally likely the coolest decade since the last glacial period — I have italicised years before 1910. (Data on a first glance suggest that during the 1900s standard shelters were in use in Melbourne much earlier than in more newly established temperature stations).

Although maximum temperatures usually occur during the hours when the Grand Final is played, it must be noted that they do not necessarily occur at this time due to abrupt wind changes. This happened, for instance in 1960 when a vigorous frontal system produced heavy rainfall before the game and drove temperatures far below the tabulated maximum.
Season Grand Final Day Tmax
1898 69.3 ˚F 20.7 ˚C
1899 57.7 ˚F 14.3 ˚C
1900 61.0 ˚F 16.1 ˚C
1901 70.7 ˚F 21.5 ˚C
1902 53.8 ˚F 12.1 ˚C
1903 76.8 ˚F 24.9 ˚C
1904 68.0 ˚F 20.0 ˚C
1905 53.8 ˚F 12.1 ˚C
1906 57.4 ˚F 14.1 ˚C
1907 72.9 ˚F 22.7 ˚C
1908 64.0 ˚F 17.8 ˚C
1909 61.0 ˚F 16.1 ˚C
1910 70.5 ˚F 21.4 ˚C
1911 60.6 ˚F 15.9 ˚C
1912 70.7 ˚F 21.5 ˚C
1913 64.8 ˚F 18.2 ˚C
1914 57.0 ˚F 13.9 ˚C
1915 61.2 ˚F 16.2 ˚C
1916 68.7 ˚F 20.4 ˚C
1917 63.9 ˚F 17.7 ˚C
1918 59.2 ˚F 15.1 ˚C
1919 79.5 ˚F 26.4 ˚C
1920 63.9 ˚F 17.7 ˚C
1921 63.9 ˚F 17.7 ˚C
1922 74.5 ˚F 23.6 ˚C
1923 69.3 ˚F 20.7 ˚C
1925 64.9 ˚F 18.3 ˚C
1926 73.9 ˚F 23.3 ˚C
1927 55.2 ˚F 12.9 ˚C
1928 61.0 ˚F 16.1 ˚C
1929 68.5 ˚F 20.3 ˚C
1930 69.6 ˚F 20.9 ˚C
1931 61.3 ˚F 16.3 ˚C
1932 61.7 ˚F 16.5 ˚C
1933 61.5 ˚F 16.4 ˚C
1934 64.0 ˚F 17.8 ˚C
1935 63.5 ˚F 17.5 ˚C
1936 69.6 ˚F 20.9 ˚C
1937 68.9 ˚F 20.5 ˚C
1938 73.9 ˚F 23.3 ˚C
1939 65.8 ˚F 18.8 ˚C
1940 54.1 ˚F 12.3 ˚C
1941 76.1 ˚F 24.5 ˚C
1942 66.7 ˚F 19.3 ˚C
1943 59.2 ˚F 15.1 ˚C
1944 85.5 ˚F 29.7 ˚C
1945 69.8 ˚F 21.0 ˚C
1946 57.2 ˚F 14.0 ˚C
1947 76.1 ˚F 24.5 ˚C
1948 59.5 ˚F 15.3 ˚C
55.2 ˚F 12.9 ˚C
1949 57.0 ˚F 13.9 ˚C
1950 70.0 ˚F 21.1 ˚C
1951 68.0 ˚F 20.0 ˚C
1952 66.9 ˚F 19.4 ˚C
1953 62.1 ˚F 16.7 ˚C
1954 57.9 ˚F 14.4 ˚C
1955 57.9 ˚F 14.4 ˚C
1956 64.9 ˚F 18.3 ˚C
1957 65.5 ˚F 18.6 ˚C
1958 52.3 ˚F 11.3 ˚C
1959 63.1 ˚F 17.3 ˚C
1960 71.1 ˚F 21.7 ˚C
1961 66.6 ˚F 19.2 ˚C
1962 57.2 ˚F 14.0 ˚C
1963 76.1 ˚F 24.5 ˚C
1964 69.4 ˚F 20.8 ˚C
1965 76.3 ˚F 24.6 ˚C
1966 56.1 ˚F 13.4 ˚C
1967 61.0 ˚F 16.1 ˚C
1968 70.5 ˚F 21.4 ˚C
1969 73.9 ˚F 23.3 ˚C
1970 57.7 ˚F 14.3 ˚C
1971 66.0 ˚F 18.9 ˚C
1972 19.3 ˚C 66.7 ˚F
1973 23.8 ˚C 74.8 ˚F
1974 17.5 ˚C 63.5 ˚F
1975 19.6 ˚C 67.3 ˚F
1976 15.8 ˚C 60.4 ˚F
1977 15.2 ˚C 59.4 ˚F
17.1 ˚C 62.8 ˚F
1978 20.7 ˚C 69.3 ˚F
1979 15.8 ˚C 60.4 ˚F
1980 18.3 ˚C 64.9 ˚F
1981 17.7 ˚C 63.9 ˚F
1982 16.3 ˚C 61.3 ˚F
1983 13.5 ˚C 56.3 ˚F
1984 12.4 ˚C 54.3 ˚F
1985 13.3 ˚C 55.9 ˚F
1986 14.7 ˚C 58.5 ˚F
1987 30.7 ˚C 87.3 ˚F
1988 18.4 ˚C 65.1 ˚F
1989 21.7 ˚C 71.1 ˚F
1990 14.0 ˚C 57.2 ˚F
1991 16.6 ˚C 61.9 ˚F
1992 15.1 ˚C 59.2 ˚F
1993 17.4 ˚C 63.3 ˚F
1994 17.8 ˚C 64.0 ˚F
1995 21.5 ˚C 70.7 ˚F
1996 18.5 ˚C 65.3 ˚F
1997 19.6 ˚C 67.3 ˚F
1998 20.7 ˚C 69.3 ˚F
1999 17.5 ˚C 63.5 ˚F
2000 17.7 ˚C 63.9 ˚F
2001 25.9 ˚C 78.6 ˚F
2002 11.9 ˚C 53.4 ˚F
2003 13.7 ˚C 56.7 ˚F
2004 18.2 ˚C 64.8 ˚F
2005 15.9 ˚C 60.6 ˚F
2006 17.8 ˚C 64.0 ˚F
2007 17.5 ˚C 63.5 ˚F
2008 24.0 ˚C 75.2 ˚F
2009 14.2 ˚C 57.6 ˚F
2010 19.9 ˚C 67.8 ˚F
21.0 ˚C 69.8 ˚F
2011 14.0 ˚C 57.2 ˚F
2012 13.5 ˚C 56.3 ˚F
2013 16.4 ˚C 61.5 ˚F
2014 23.4 ˚C 74.1 ˚F
2015 31.3 ˚C 88.3 ˚F
2016 18.6 ˚C 65.5 ˚F
2017 15.4 ˚C 59.7 ˚F
2018 14.0 ˚C 57.2 ˚F
2019 14.9 ˚C 58.8 ˚F
2022 14.7 ˚C 58.5 ˚F
2023 29.7 ˚C 85.5 ˚F
2024 22.0 ˚C 71.6 ˚F
2025 19.5 ˚C 67.1 ˚F

Graph of Grand Final Day Temperatures and 5-Year Mean:

Maximum Temperatures in ˚C on Each VFL/AFL Grand Final Day in Melbourne (all data courtesy of Australian Bureau of Meteorology)

If we look at this graph, it is difficult to detect the global warming produced by the huge fossil fuel production for the profit of Australian coal barons and Persian Gulf oil sheikhs. This, of course, is substantially a reflection of small sample size. There are, indeed, many cases where a change of merely one day would produce a radically different temperature. For instance, in 1928 and 2008, the preceding Friday exceeded 29˚C.

However, very hot Grand Final days seem to have become more frequent, as seen by two such days in 2015 and 2023 equalling the total before 2015 [from 1944 and 1987].

One interesting fact is that both the hottest and the coolest Grand Final days seem to occur mostly in years of widespread droughts. The very hot Grand Finals of 1944 and 2015, and the very cool Grand Finals of 1902, 1940, and 2002, all occurred in years of extreme drought in various parts of Victoria and adjacent states. So did several slightly less hot or cool Grand Finals like 1946 (cool) and 1965 (hot). A plausible explanation for this is that exceptionally hot and exceptionally cool temperatures are both dependent on dominant anticyclones driving air from Central Australia (very hot weather) or Antarctica (very cool).

Another notable fact is that changes in the date of the Grand Final (not shown) do not seem to have had much effect upon temperatures. The earlier Grand Final (1916, September 2) was very nearly so hot as the latest one (1923, October 20) whilst the two hottest pre-Kyōtō Protocol Grand Finals were both played in September not October. Of other Grand Finals played with temperatures above 23.9˚C — well and truly warm enough to wear shorts and a T-shirt — only 1919 and 1963 were played in October, whilst 1903, 1941, 1947 and 1965 were played in September. [Regarding the reliability of temperature data from 1903, newspaper reports do suggest strongly the weather was very warm].

Wednesday, 26 November 2025

All Tmin seasonal inversions in Melbourne

In my previous post, I made a brief discusison of the phenomenon of “seasonal inversions” over Melbourne and more generally over Victoria. Major “seasonal inversions” are rare but by no means unknown in southeastern Australia. The previous post shows seven clear cases of Tmean inversion outside of the summer months over Victoria since 1910, and available temperature data from earlier years strongly implies four or five more between 1855 and 1909. There are two further cases of Victoria-wide Tmax inversion only since 1910, whilst October-November 1866 and September-October 1864 look likely from the Melbourne data but have no means for further investigation, at least those accessible to myself.

Tmin inversions, as I noted, were about four times more frequent than Tmax or Tmean. Therefore, I decided to ignore them for an extension of my previous post, but after a further thought I felt that I should list all Tmin inversions in Melbourne — based upon the previous criteria — since records began in 1855.

All Tmin Seasonal Inversions in Melbourne Since 1855: 

Tmin Change  
1859 August 6.87 -0.13  
September 6.74
1863 July 6.83 -0.52 Unusual inversion in that July was quite dry and August very wet (sixth-wettest in the records). This suggests very foggy conditions, but cloudiness data do not suggest exceptional gloominess
August 5.09
September 6.31
1866 October 9.35 -0.79 As noted previously, mean minimum for November cooler than for May, and was even so in Adelaide [52.8˚F or 11.56˚C in May; 52.4˚F or 11.33˚C in November]
November 8.57
1870 May 6.34 -1.02 Almost certainly wettest year over Victoria — estimated state mean possibly greater than one metre — with particularly wet conditions in winter and spring. Very high cloudiness (7.7/10 in June versus mean of 6.6) and warm mornings explains large inversion
June 7.36
1871 April 8.96 -0.03  
May 8.99
1872 May 7.25 -0.65 Another exceedingly wet winter throughout the state, with again very high cloud amount (7.5/10)
June 7.90
1873 August 7.26 -0.08  
September 7.18
October 9.49 -0.15 Very small compared to large Tmax inversion discussed in earlier post.
November 9.35
1874 October 9.70 -0.02  
November 9.68
1875 May 7.32 -0.28  
June 7.61
August 6.65 -0.07  
September 6.58
1877 October 8.45 -0.33 November mean minimum coolest on record. Like 1866, the mean was cooler than for May.
November 8.11
1878 September 8.09 -0.35  
October 7.74
1880 September 8.26 -0.75 Third-wettest September on record in Melbourne after 1916 and 1870, with extreme flooding in Gippsland, where it was comparably wet to 1934–35, 1952 and 1978
October 7.51
1881 August 7.19 -0.23  
September 6.96
1883 May 6.89 -1.90 Largest Tmin inversion on record in Melbourne. Although as I have noted Tmin inversions are much more common than Tmax, this inversion is smaller than the Tmax inversion between October and November 1940.
June 8.79
1890 May 8.01 -0.87 The last two of three consecutive extremely wet Junes over Victoria, with consequent high cloud cover.
June 8.89
1891 May 7.27 -0.29
June 7.56
1894 August 6.74 -0.31  
September 6.43
1895 August 7.65 -0.45  
September 7.20
1898 May 6.45 -0.16 Notably cool and very blocked May followed by Australia’s ninth-wettest June since 1890 — very cool in Western Australia, but warm in east
June 6.61
1899 September 8.46 -0.31  
October 8.15
1904 August 6.60 -0.34  
September 6.26
1905 March 11.32 -0.02 Extremely dry March virtually throughout Australia followed by very wet April in Murray–Darling Basin. Likely wettest on record in North Mallee.
April 11.34
August 6.11 -0.54 Record cool spell from 15 September to end of month with mean maximum of 12.225˚C — no day reaching 14˚C — and mean minimum of 5˚C.
September 5.57
1911 April 9.44 -0.19 All these inversions were replicated throughout Victoria as a whole, though none are large. May 1912 is the driest May on record over the Murray–Darling Basin
May 9.63
1912 May 6.52 -0.29
June 6.81
1913 October 9.62 -0.01
November 9.61
1915 September 8.70 -0.03 Coolest September on record in Perth, hottest in Brisbane, and wettest until 2016 in South Mallee and Wimmera districts
October 8.67
1916 September 9.36 -0.40  
October 8.96
1920 May 7.51 -0.44 Coolest May of twentieth century followed by wet and windy June, beginning what would be Australia’s last big wet spell until 1939.
June 7.95
1928 September 9.45 -0.72  
October 8.73
1931 April 8.86 -0.84 Notably large inversion due to warm, cyclonic May amidst a very wet spell widely noted in Every Game Ever Played.
May 9.70
1932 September 7.78 -0.24 Unusual inversion between dry September and wet October, especially as not due to excessive fogginess (September 1932 cloud amount 6.1/10; similarly dry May 1932 7.1/10) and no Tmax inversion.
October 7.54
1934 July 6.829 -0.446 Extremely cool September following warm July that saw 20˚C reached in the month for only the second time on record
August 6.384
September 6.383
1935 August 7.36 -0.44  
September 6.92
1936 July 6.15 -0.01 Extremely wet winter — third-wettest July on record over Melbourne — followed by cool September as noted in previous post
August 7.04
September 6.13
1942 April 10.12 -0.19 Record wet May in Melbourne and many other parts of Victoria and inland New South Wales. Fourth-wettest over Australia as a whole after 1921, 1955 and 1968.
May 10.31
1945 August 7.62 -1.07 Fifth-largest Tmin inversion on record, and replicated all through Victoria. August was fairly wet — very much so in southwestern Australia and Tasmania — but September distinctly dry over all of Victoria outside south Gippsland.
September 6.55
1946 July 7.29 -0.15 Extremely windy westerly July — very wet in Northeast, South Wimmera and West Coast, almost rainless in Queensland and New South Wales away from Southwest Slopes and Snowy Mountains — amidst long sequence of cool anticyclonic months. Total runoff into Perth’s dams in July 1946 alone greater than for the entire decade 2006 to 2015.
August 6.40
September 7.14
1948 March 10.37 -0.38 Extremely cool, dry southerly March followed by wet April in west and east — wettest ever in North Wimmera district
April 10.75
1949 July 6.21 -0.07 Coolest year over Victoria since 1910 with what the New South Wales Yearbook called an “early spring” due to the less cool July — followed by one of Victoria’s driest Augusts on record with consequent cold mornings — though less cold than 1943 or 1944.
August 5.35
September 6.14
1952 May 7.64 -0.33  
June 7.97
1955 October 9.64 -0.13  
November 9.51
1957 May 8.02 -1.38 Record hot June throughout Victoria discussed previously, although Tmin inversion may not rival that of May and June 1883.
June 9.39
1958 April 9.62 -0.39 Very dry April in Victoria — driest since 1923 in West Gippsland — followed by extremely wet and warm May throughout southeastern Australia and especially Tasmania where it rivals May 1923 as that state’s wettest month since 1890.
May 10.02
August 7.23 -0.62 Very wet August in Victoria followed by cool September with persistent anticyclones over Tasmania. Includes coolest V/AFL Grand Final Day on record (11.3˚C).
September 6.61
1960 October 9.69 -0.47  
November 9.21
1961 May 7.91 -0.14  
June 8.05
1962 May 8.25 -0.08 Tmin inversion here very small, but part of a remarkably close pair of May-June Tmean inversions (two of three over 170 years in a five-year span)!
June 8.32
1963 April 9.29 -0.32 Driest April since 1923 over southwestern Victoria followed by record gloomy May with only 1.6 hours of sunshine per day in Melbourne
May 9.61
October 12.22 -1.24 Hottest October until 2015 with very warm, humid northeasterly winds followed by southerly November with (near)-record dryness in Western Victoria and South Australia
November 10.97
1965 October 11.09 -0.14  
November 10.95
1969 August 8.16 -0.49 Two of the major seasonal inversions over southeastern Australia since 1910.
September 7.67
1977 August 8.48 -0.91
September 7.58
1978 April 10.85 -0.06  
May 10.92
1981 September 10.14 -0.06  
October 10.09
1982 August 7.90 -0.62 Both of these are part of full Tmean inversions in Melbourne, though not replicated over Victoria as a whole.
September 7.28
1984 August 8.67 -0.39
September 8.28
1991 May 9.18 -0.50 Extremely dry May followed by record warm and wet June — sixth-wettest month over Victoria since 1890.
June 9.68
October 11.62 -0.43 Very hot and dry October — driest since 1914 over Mallee, North and alpine areas, and hottest since 1963 — followed by extremely cool summer beginning in November. Alongside 1914, only year when 30˚C was reached more often in October than in December.
November 11.19
1992 July 7.64 -0.05 Record wet August to December spell — only case of four consecutive months over 100 millimetres in Melbourne, and only September that never reached 20˚C
August 6.57
September 7.60
1995 April 9.50 -0.04 Coolest April in Melbourne since 1951, and (Tmin) inversion extended to Victoria as a whole.
May 9.54
July 7.30 -0.19 Famously hot and dry August throughout southern mainland Australia preceded by wet westerly July and followed by cool September with heavy rain on the New South Wales coast but continuing dry conditions in Victoria away from East Gippsland.
August 7.46
September 7.27
1998 September 10.46 -0.39  
October 10.07
1999 April 10.32 -0.05 April extremely hot in southwestern Australia, but distinctly cool in the east.
May 10.38
2007 April 12.31 -0.26 Record hot May, beating 141-year-old record in Melbourne.
May 12.57
2008 May 9.04 -0.79 Unusual Tmin inversion during very dry, but foggy — I recall the long periods of still fog early in the month — June. Foggy, dry, warm anticyclonic easterly conditions widespread over Victoria.
June 9.83
2013 September 11.18 -0.06
October 11.12
2016 September 10.09 -0.05 Wettest September on record over eastern Australia — and wettest winter half-year month over Murray–Darling Basin — followed by coolest October over eastern Australia since 1982
October 10.03

Conclusions:

  1. In Melbourne since 1885 there have been about seventy Tmin seasonal inversions between March and June or between August and November, or about two every five years.
    • in contrast, there have been only 31 Tmax or Tmean inversions over the same timespan
    • six Tmin seasonal inversions (in 1863, 1934, 1936, 1946, 1992 and 1995) extend from July to September
    • seven years (1873, 1875, 1905, 1958, 1963, 1991 and 1995) had Tmin inversions in both autumn and spring.
    • Contrariwise, no year has ever had multiple Tmax or Tmean inversions
  2. Despite the much greater frequency of Tmin inversions vis-à-vis either Tmax or Tmean
    • the greatest magnitude of a Tmin inversion is nonetheless 0.65˚C smaller than for the Tmax inversion between October and November 1940
    • that greatest magnitude is still 0.75˚C greater than for the largest Tmean inversion between May and June 1957
  3. There may be a possible reduction in magnitude of Tmin inversions due to greenhouse gas emissions to enrich Gulf oil sheikhs and Australian coal barons:
    • No Tmin inversion (of eighteen) since 1963 has exceeded 1.0˚C in magnitude
    • Contrariwise, up to 1963 there were five Tmin inversions exceeding 1.0˚C in magnitude, or one every twenty-one years
  4. It is possible that the shift in temperature and rainfall reporting station since 2015 could reduce the frequency of Tmin inversions over Melbourne:
    • There has been no Tmin inversion over Melbourne since November 2016
    • However, there has been two Tmax [September-October 2023, August-September 2024] and one Tmean [September-October 2023] inversion in this timespan not replicated over Victoria as a whole
      • It is possible that differences in location could make Tmin inversions less likely, but I have not looked at how the change would do thus

Tuesday, 25 November 2025

“Seasonal inversions” in Victorian climate history

Two years ago, it occurred quickly to me that an extremely unusual thing was happening in Melbourne. For 2023, October was cooler than September — and by mean maximum temperature, substantially so. October 2023 average 19.2˚C, and September 2023 averaged 20.1˚C — a figure of course inflated by the greenhouse gas emissions of Australia and the Gulf States, but this should not alter the abnormality being described.

The same thing happened in 2024, when Melbourne’s maximum temperature for August was 0.5˚C hotter than for September.

Studying climate history, I have always noticed that such abnormalities, whilst unusual, are not unprecedented. Although the Bureau of Meteorology says that:

“Temperature data prior to 1910 should be used with extreme caution as many stations, prior to that date, were exposed in non-standard shelters, some of which give readings which are several degrees warmer or cooler than those measured according to post-1910 standards.”

Ever since reading old Australian climate data books from the 1930s, I have known of a number of cases since the earliest temperature records were taken from Melbourne in 1856. If the note of the Bureau is correct, the fact that temperature records before 1910 “should be used with extreme caution” would not invalidate these “seasonal inversions”, at least if they be observed at every available station within an area.

For this post, I intend to tabulate cases where any of the following occurred over Victoria as a whole since 1910:
  1. April hotter than March
  2. May hotter than April
  3. June hotter than May
  4. September cooler than August
  5. October cooler than September
  6. November cooler than October
Seasonal inversions can occur in any one or more of maximum, minimum or mean temperature. Logically, the last of these is the most accurate. However, over the years my primary focus has been on memorising and collecting mean maximum temperatures, and I have known of inversions in minimum temperatures that did not extend to maximum or mean temperatures.

Months Since 1910 with Victoria-Wide Seasonal Tmean Inversion:

Tmax Tmean Tmin
1928 September 18.56 12.50 6.44
October 17.83 12.07 6.29
1940 October 22.13 15.08 8.03
November 21.49 14.82 8.22
1957 May 16.03 10.27 4.59
June 16.64 11.50 6.37
1962 May 14.66 9.97 5.36
June 14.46 10.26 6.05
1969 August 14.59 9.49 4.28
September 13.41 8.87 4.31
1977 August 16.18 10.51 4.73
September 15.72 9.99 4.25
2001 September 18.42 12.97 7.51
October 17.94 12.68 7.41

Months Since 1910 With Victoria-Wide Seasonal Tmax Inversion Only

Tmax Tmean Tmin
1982 August 17.18 10.73 4.17
September 16.77 10.78 4.76
2015 October 25.29 17.64 9.99
November 24.62 17.72 10.92

Months Since 1910 With Victoria-Wide Seasonal Tmin Inversion Only

Tmax Tmean Tmin
1911 April 18.20 12.08 5.95
May 15.62 11.05 6.56
1912 May 16.57 10.06 3.63
June 12.86 8.70 4.52
1913 October 20.36 14.12 7.88
November 21.18 14.30 7.51
1920 May 14.49 9.18 3.95
June 12.73 8.85 4.97
1923 October 18.64 13.04 7.42
November 21.26 14.18 7.18
1931 April 18.22 12.90 7.57
May 15.26 11.39 7.62
1932 September 16.62 11.54 6.46
October 17.59 11.68 5.76
1936 August 14.03 9.58 5.02
September 15.35 9.70 4.03
1942 April 19.32 13.81 8.29
May 15.30 11.78 8.36
1945 May 15.64 10.23 4.90
June 14.02 9.70 5.37
August 13.89 9.67 5.35
September 15.68 10.28 4.86
1948 March 22.78 15.34 8.09
April 19.00 13.56 8.11
1954 March 23.56 15.91 8.43
April 20.40 14.65 8.90
1955 October 19.01 13.49 7.96
November 20.40 13.92 7.53
1958 April 21.60 14.54 7.48
May 16.63 12.55 8.57
August 12.75 9.07 5.27
September 14.83 9.67 4.49
1961 May 16.18 10.29 4.49
June 14.11 9.45 4.79
1963 April 19.56 13.27 6.96
May 15.19 11.58 8.07
October 21.56 15.38 9.19
November 22.83 15.87 8.98
1991 May 16.79 11.29 5.89
June 14.62 11.14 7.65
1992 October 19.02 13.83 8.65
November 19.64 14.04 8.53
1995 April 17.69 12.32 6.93
May 15.20 11.13 7.15
1999 October 20.53 14.66 8.78
November 21.37 14.74 8.20
2004 May 15.93 10.61 5.37
June 13.23 9.43 5.62
2008 May 16.30 11.25 6.29
June 14.74 10.58 6.42
2013 September 18.93 13.52 8.11
October 20.00 13.70 7.39
2023 May 15.39 10.57 5.84
June 13.69 9.93 6.16
It is immediately obvious that Tmin seasonal inversions (32 Victoria-wide since 1910) are significantly more common than Tmean (seven) or Tmax (eight). There have been on average four Tmin inversions every fifteen years, but Tmax and Tmean inversions occur only on average every fifteen to sixteen years. For this reason, when using Melbourne data for likely large-scale inversions predating 1910, I will consider only Tmean and Tmax for the table below.

All Months with Seasonal Tmean and/or Tmax Inversion in Melbourne:

Year Months Tmax Tmean Δmax Δmean Notes
1864 September 18.48 13.69 -0.69 -0.24
October 17.79 13.45
1866 October 20.48 14.94 -0.16 -0.48 Minimum temperature in November 1866 cooler than for May!
November 20.32 14.46
1873 October 21.31 15.41 -1.48 -0.84 Extremely large seasonal inversion. Data inadequate to demonstrate accuracy, but unlikely that so large an inversion — fifth-largest on record in Melbourne — could be due to different shelters.
November 19.83 14.57
1883 May 16.20 11.55 0.62 -0.64 Inversion replicated in Hobart data — it is the first full year of temperature recording there.
June 15.58 12.19
1886 September 18.53 13.07 -1.07 -0.49 Unusual La Niña seasonal inversion due to major Tasman Sea block that saw Brisbane have wettest September on record and Cairns second-wettest. Melbourne had hottest September until 1919, and inversion strongly replicated in Hobart data.
October 17.46 12.58
1888 March 20.67 15.79 -0.47 0.97
April 21.14 14.82
1899 September 17.76 13.13 0.25 -0.07
October 18.01 13.06
1904 March 20.12 15.81 -1.67 -0.34 Coolest March on record — after cool pluvial summer that saw Wilfred Rhodes, utterly hopeless on his other Australian tours, manage 31 Test wickets — followed by extremely dry April. Hobart had just two raindays all April. Seasonal inversion replicated by Hobart and Adelaide data.
April 21.79 16.15
1905 August 14.59 10.35 -1.06 -0.78 Extraordinary cool spring spell. Both September and October easily coolest on record, and the last fortnight of September did not reach a maximum of 14˚C! Inversion replicated in Hobart data.
September 13.53 9.57
1919 March 20.67 15.79 -0.47 0.97 Second-wettest March in Melbourne followed by dry April with springlike flowers
April 21.14 14.82
1928 September 19.50 14.50 -0.94 -0.87 Major seasonal inversion replicated in all-Victoria data. Hottest September in Melbourne until 2013, with first-ever 30˚C day in that month, and then extremely wet October in exposed Upper Northeast and West Coast.
October 18.56 13.63
1936 August 15.33 11.17 0.50 -0.20 Extremely wet winter followed by extremely cool anticyclonic September. Mean minimum for September was 0.01˚C cooler than July [September 6.13˚C; July 6.14˚C] and second-coolest on record [September 1949 was 6.136667˚C against September 1936’s 6.13333˚C and September 1905’s 5.57˚C].
September 15.83 10.97
1940 October 23.32 16.36 -2.55 -0.77 Hottest October mean maximum in Melbourne until 2015, followed by cool, rainy November in southern Victoria and Wimmera. Largest seasonal inversion in Melbourne on record by Tmax, although weaker than September-October 1928 over Victoria as a whole.
November 20.77 15.59
1948 September 18.75 13.13 -0.29 0.15
October 18.46 13.28
1957 May 16.77 12.39 -0.94 -1.17 Largest seasonal inversion on record by mean temperature in both Melbourne and all-Victoria data. First half of June saw all records for heat in that month broken
June 17.71 13.56
1960 October 20.40 15.05 -0.43 -0.46 Despite exceptional rains in November — Adelaide had 75 millimetres in one day — inversion not replicated across Victoria.
November 19.97 14.59
1962 May 15.77 11.99 -0.15 -0.12
June 15.92 12.11
1963 October 21.81 17.01 0.21 -0.50 Hottest October in Melbourne by Tmean until 2015, and hottest in Hobart to date. This is the only 1960s October-November inversion replicated there, but very strongly.
November 22.02 16.51
1965 October 21.35 16.23 -0.22 -0.16
November 21.13 16.07
1969 July 15.15 10.83 -1.31 -0.90 Major, widespread inversion throughout southeastern Australia. In Adelaide, the mean minimum for September was more than 1˚C cooler than for any of the “winter” months! Three-month Tmax inversion unique for Melbourne but not replicated throughout Victoria.
August 15.58 11.89
September 14.27 10.99
1973 October 20.27 15.74 -0.34 0.28 Melbourne did not reach 28˚C in all of November, although inversion not replicated for the Victoria-wide data.
November 19.93 16.02
1977 August 16.45 12.48 -1.08 -0.99 Hottest August mean maximum in Melbourne until 1982, and driest since 1944. September was extremely cool in first half, but varied from record dry in South Gippsland and northern Tasmania to extremely wet in East Gippsland.
September 15.37 11.49
1982 August 17.73 12.82 -0.72 -0.66 Hottest, and third-driest, August across Victoria as a whole. Hottest in Melbourne until 2024.
September 17.01 12.16
1984 August 15.42 12.06 0.14 -0.13 Unlike 1977 and 1982, this was a very wet August, but minima were extremely high due to cloudiness. September was also very wet but long periods late in the month were dominated by an anticyclone to the west of Victoria.
September 15.56 11.93
1993 August 17.38 12.79 -0.05 0.73
September 17.33 13.52
1995 August 16.99 12.25 -0.11 -0.16 Famous hot and dry August across southern mainland Australia — Sydney went 46 days without rain and Melbourne had more afternoons above 20˚C than in August 1982.
September 16.88 12.09
2005 March 23.91 18.81 -0.18 0.01 Hottest April and driest autumn on record throughout Victoria.
April 24.09 18.80
2013 September 20.06 15.62 -0.22 -0.15 Hottest September on record in Victoria.
October 19.84 15.47
2015 October 24.32 18.34 -1.60 -0.49 Record hot and dry October across Victoria and especially western Tasmania. In normally wet Waratah there were only two raindays and it was the second-driest month on record after March 1893.
November 22.72 17.85
2023 September 20.11 14.88 -0.86 -0.04 Record hot and dry September followed by very wet October across eastern Victoria where bushfires turned into floods in a few hours. October was though even drier and relatively hotter than September in more westerly parts of Australia.
October 19.25 14.84
2024 August 18.25 13.83 -0.48 0.11
September 17.77 13.94
The figures from Melbourne indicate highly probable widespread seasonal inversions before 1910 in:
  1. October-November 1873
    • only because the magnitude of the inversion in Melbourne is so large that it could hardly have been not replicated more widely
  2. September-October 1886
  3. March-April 1904
  4. August-September 1905
    • newspapers from this period do provide conclusive evidence that the spring of 1905 was uniquely cool even for a decade that is probably the coolest globally since the last glacial.
In contrast to the spring of 1905, documentary evidence for the previous three cases was not found when I checked Trove. Even the 1905 newspapers do not note that figures indicate September was cooler than August. This suggests that earlier probable inversions with even poorer and less reliable temperature data are unlikely to be confirmable via pure documentary evidence.

For the next part of this study, I will extend the analysis to all Tmin inversions in Melbourne since data began in 1855.