Victor Conrad’s missing data

Ever since reading Robert Dewar and James Wallis’ ‘Geographical Patterning of Interannual Rainfall Variability in the Tropics and Near Tropics’ about two decades ago, it has occured to me that when the authors say:

“Conrad mapped variability in precipitation for the entire world, using records from 384 stations. For the area between 30˚N and 30˚S, he had 149 stations.”

Yet, Dewar and Wallis fail to note that for many of the high-variability regions they discuss, Conrad had no stations whatsoever. This is true particularly for:

1. Queensland
2. eastern Melanesia (the “Fiji–New Caledonia” region of Ropelewski and Halpert)
• of the regions discussed by Ropelewski and Halpert as having coherent El Niño Southern Oscillation precipitation responses, “Fiji–New Caledonia” is the only one where all stations in Dewar and Wallis’ database are “highly variable”
3. northwestern coastal Australia
4. coastal Angola
5. eastern Kenya and Somalia (“Greater Somalia”)
• if you read ‘Geographical Patterning of Interannual Rainfall Variability in the Tropics and Near Tropics’ you will see that Dewar and Wallis do discuss the Horn of Africa as noted by Conrad
• in reality, Conrad had no stations between Zanzibar and Aden, nor in present-day Ethiopia or Eritrea
6. Baja California
• of all the high-variability regions in the 1999 dataset, Baja is undoubtedly the most “excusable”, at least in the sense that no data for the region existed as of 1928 when Conrad’s data was collected

Asking the question on Google, I have discovered that the reason most of Australia and eastern Melanesia were unsampled in Victor Conrad‘s 1941 study. Apart from a few stations published in Quarterly Journal of the Royal Meteorological Society — which were those listed by Conrad — Australia’s large assembly of meteorological records was some of the world’s most extensive but also most fragmented:

1. before the formation of the national Bureau of Meteorology (BoM) in 1908, rainfall data was collected independently by individual Australian colonies (states like New South Wales, Queensland, etc.)
2. each colony or state published its own monthly meteorological summaries
3. these were mostly distributed locally or held in national and state archives and libraries rather than in global meteorological circulars
4. records were held locally or in state archives like the Australian Bureau of Meteorology’s state volumes
1. the great majority of stations in Australia (and Melanesia) thus had their records published only in state-specific histories and never in global summaries
2. the vast majority of high-quality long-term records remained “buried” in colonial-era journals, ship logs, or government documents
3. global sources like Smithsonian’s World Weather Records rarely carried data from these regions

Most Australian and Melanesian meteorological records when Conrad was writing were thus localised and inaccessible to international researchers, being not yet integrated into widely-circulated international compendiums. The most important of these were the UK’s Meteorological Office and the Smithsonian Institution’s World Weather Records.

Even so, one might argue that articles like Steven Sargent Visher’s ‘Variability Versus Uniformity in the Tropics’ published nineteen full years before Conrad’s work should have provided enough data for Onslow and perhaps other parts of tropical Australia. It is possible that the raw data used by Visher were not kept in his archives, but the basic information should have been available to Conrad yet he clearly did not use it.

What I will do below is:

1. select a representative list of stations in areas of Australia not covered by Conrad
1. only data from 1928 and before — when his first data were compiled — are included
2. data will be done in a calendar year format as they were done by Conrad
3. data will be tabulated as Conrad did for his actual stations, although I have omitted latitude and longitude
4. I have deviated from Conrad in ordering stations by region in a clockwise order, rather than purely by longitude as Conrad did
2. compile:
1. mean annual rainfall by calendar year to 1928
2. average departure from the mean, and then comparing it in two ways with Conrad’s expected value:
1. by simple difference, as Conrad did
2. by ratio to expected average deviation minus 100 percent

Method 2) was added because studying Conrad’s article does suggest that areas of high rainfall but abnormal variability are not easily identified by mere difference from expected value. Of the few high-variability regions identified by Dewar and Wallis for which Conrad did have data, two — the northern South China Sea region and lowland eastern Indonesia — were not identified by Conrad as regions of abnormal variability, not discussed as such. This despite the fact that Nha Trang and Ambon Island were shown as having a variability that was clearly exceptional, whilst nearby stations had sufficiently high variability that a pattern could quite likely have been recognised. Conrad’s failure to recognise the northern South China Sea and lowland eastern Indonesia as areas of unusual rainfall variability related to his use of arithmetic rather than geometric (as used by Dewar and Wallis and by Pierre Camberlin’s 2010 ‘More variable tropical climates have a slower demographic growth’) departure.

Explanatory Shading:

1. Departures above 20 percent or more than twice Conrad’s expected value have been shaded in dark red
2. Departures above 10 percent but below 20 percent or more than 1.5 times but less than than twice Conrad’s expected value have been shaded in red
3. Departures above 5 percent but below 10 percent or more than 1.25 times but less than than 1.5 Conrad’s expected value have been shaded in pink
4. stations who departure is less than 5 percent and/or less than 1.25 times Conrad’s expected value are unshaded

Representative Stations from Areas of Australia Unrepresented in Conrad’s Study (Courtesy Australian Bureau of Meteorology):

Region	Station	Elevation		Mean		Average deviation		Percent	% deviation from expected	departure as % of expected
		feet	metres	inches	millimetres	inches	millimetres
Tropical Queensland	Boulia	532	162	10.6	269	5.53	141	52%	+28%	+117.43%
	Burketown	20	6	27.9	709	10.04	255	36%	+18%	+99.70%
	Coen	653	199	46.7	1,187	11.47	291	25%	+9%	+58.37%
	Cooktown	20	6	69.9	1,775	17.23	438	25%	+10%	+64.36%
	Innisfail	33	10	142.8	3,627	26.13	664	18%	+4%	+30.71%
	Townsville	13	4	47.3	1,203	13.59	345	29%	+13%	+79.46%
	Rockhampton	36	11	39.2	995	10.70	272	27%	+11%	+70.65%
	Barcaldine	876	267	19.8	502	6.86	174	35%	+16%	+87.67%
Murray–Darling Basin	Roma	981	299	23.6	599	6.87	174	29%	+11%	+61.80%
	Tamworth	1,326	404	26.8	682	5.07	129	19%	+1%	+4.95%
	Dubbo	853	260	22.2	563	5.22	133	24%	+6%	+30.82%
	Albury	515	157	27.9	709	4.72	120	17%	-1%	-6.02%
	Wentworth	121	37	11.8	301	3.13	79	26%	+4%	+19.96%
Western Interior	Daly Waters	696	212	26.4	670	6.71	170	25%	+7%	+41.29%
	Tennant Creek	1,237	377	14.4	366	5.10	129	35%	+15%	+77.03%
	Moonaree	787	240	7.4	187	2.44	62	33%	+6%	+22.76%
	Wiluna	1,709	521	9.6	244	3.18	81	33%	+8%	+32.48%
	Mount Magnet	1,398	426	9.4	239	3.53	90	38%	+13%	+50.14%
	Halls Creek	1,181	360	21.0	532	6.04	154	29%	+11%	+60.25%
West Coastal	Geraldton	10	3	18.5	469	3.87	98	21%	+2%	+13.36%
	Carnarvon	16	5	9.5	241	3.61	92	38%	+13%	+52.57%
	Onslow	13	4	9.0	228	5.46	139	61%	+36%	+143.67%
	Roebourne	39	12	11.7	297	4.78	121	41%	+19%	+86.16%
	Derby	26	8	25.8	655	8.01	204	31%	+13%	+72.53%
Southern Coastal	Bega	164	50	33.5	852	9.25	235	28%	+11%	+62.23%
	Melbourne	102	31	25.5	648	3.78	96	15%	-3%	-17.66%
	Hobart	171	52	23.9	608	4.26	108	18%	0%	-1.18%
	Eucla	305	93	10.0	253	2.13	54	21%	-3%	-10.88%
	Albany	10	3	37.3	947	4.98	127	13%	-3%	-18.98%

Results:

The results clearly show that if Conrad could have obtained existing data for tropical Queensland — extending into the extreme northern Murray–Darling Basin represented by Roma — and the north of Western Australia, he would have recognised them as regions of abnormal rainfall variability analogous to Northeastern Brazil and the northwestern Indian subcontinent. This is true even if we use Conrad’s arithmetic departure method. By geometric departure, as I presumed, tropical Queensland appears somewhat more variable relative to Conrad’s calculated expected value, and the southern arid zone less so. This difference, however, is less than I anticipated.

It is quite possible that had Conrad some of the data tabulated above, he would have seen the two as one region of unusual rainfall variability: the figures for the central Northern Territory [Tennant Creek and Daly Waters] make this quite plausible. However, mechanistically, Queensland is more closely related to lowland eastern Indonesia and eastern Melanesia than to northwestern Australia. The high variability of the latter region is purely due to dependence for rainfall upon random tropical cyclonic disturbances that frequently produce a year’s rain in two or three days. Contrariwise, lowland eastern Indonesia, eastern Melanesia, and almost all of Queensland owe their high variability to lying in the core of the “ENSO horseshoe” where convection is most sensitive to El Niño and La Niña events. The geometric departures in Boulia and Burketown, it might be noted, are only slightly higher than Conrad tabulated for Ambon Island [+87 percent].

The south coast of New South Wales, represented by Bega, is similar to northwest Australia in owing its high variability to distinctly random Tasman Sea cyclones producing exceptionally heavy rainfall.

The remaining unsampled regions of Australia — tabulated here for both fairness and completeness — do not show much surprise in light of later studies like those of Dewar, Eddie van Etten and Camberlin.

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].

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 T_mean 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 T_max 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.

T_min inversions, as I noted, were about four times more frequent than T_max or T_mean. 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 T_min inversions in Melbourne — based upon the previous criteria — since records began in 1855.

All T_min 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 T_min seasonal inversions between March and June or between August and November, or about two every five years.
• in contrast, there have been only 31 T_max or T_mean inversions over the same timespan
• six T_min 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 T_min inversions in both autumn and spring.
• Contrariwise, no year has ever had multiple T_max or T_mean inversions
2. Despite the much greater frequency of T_min inversions vis-à-vis either T_max or T_mean
• the greatest magnitude of a T_min inversion is nonetheless 0.65˚C smaller than for the T_max inversion between October and November 1940
• that greatest magnitude is still 0.75˚C greater than for the largest T_mean inversion between May and June 1957
3. There may be a possible reduction in magnitude of T_min inversions due to greenhouse gas emissions to enrich Gulf oil sheikhs and Australian coal barons:
• No T_min inversion (of eighteen) since 1963 has exceeded 1.0˚C in magnitude
• Contrariwise, up to 1963 there were five T_min 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 T_min inversions over Melbourne:
• There has been no T_min inversion over Melbourne since November 2016
• However, there has been two T_max [September-October 2023, August-September 2024] and one T_mean [September-October 2023] inversion in this timespan not replicated over Victoria as a whole
• It is possible that differences in location could make T_min inversions less likely, but I have not looked at how the change would do thus