The ABC reports Adelaide CBD records coldest morning since 1944 as ice forms on River Torrens – I had been watching this cold spell for a few daze. Cooma Airport AWS 70217 has seen the coldest first 10 days of June (-3.24) since 2000 which averaged -3.81. I have not checked Canberra. The Minimum Temperature Outlook for June issued on 28 May predicts warm anomalies for June. The Minimum Temperature maps for 5th June shows the SE Australian cool patch and you can easily explore forward or back from there as the month progresses.
Would this just be indicating that there are not many clouds about and that it is very dry around Cooma as we are still in drought down here? Deserts are very cold places at night and it looks like a desert or Mars ATM. If there are fogs the temperature stays a balmy 2 to 5 degrees day and night this time of year. Also the BOM predicted rain, so it is more likely we wont get any than we will.
It's a been very cold start to June here 10km south of Castlemaine. The minimum thermometer at the BOM Castlemaine weather station within the precinct of Loddon Prison seems to dislike the cold judging from the missing minimums in data recorded so far. I have added my minimum readings to a screenshot of the BOM data to date 11/6.
Looks like another cold morning coming up tomorrow.
My attention was caught hearing about discussion on ABC radio re the 5th June min reading at High Range ~east of Taralga nd NNW of Moss Vale. Listeners were reported as saying there was a frost at High Range near the AWS but the AWS was not indicating that. I saw that Moss Vale had 5th 6th & 7th sub 0 and is closer to the coast than High Range. Hence my interest then the ABC wrote on the Adelaide ~75yr record.
Minimum temperature here today was -1.0. The BOM Castlemaine site has been removed from the Latest Weather Observations for Victoria list, presumably to fix their minimum temperature thermometer. They had trouble with this device a few years ago, also at a time when we were having some cold minimum temperatures?
Not sure it’s relevant but looking at the CSIR’s Meteorological Data for Certain Australian Localities, published in 1933, Adelaide had an average June minimum of 8.2C and maximum of 15.8C in the 74 years of observation up to 1931.
Kent Town 23090 since 1977 has had an average June minimum of 8.1C and maximum of 16.1C.
So a mean June temperature increase of 0.1C, which isn’t a bad effort considering there’s a lot more tarmac, concrete and vehicles in Adelaide now than in the 74 years to 1931.
Since 2010, Kent Town has had an average June minimum of 7.9C and maximum of 16.2C.
So the mean June temperature of Adelaide is now 12.0C, compared to 12.0C from 1857 to 1931.
Average June rainfall 1857-1931 = 78.5mm, Kent Town 1877-2019 = 78.1mm, Kent Town 2010-2019 = 72.4mm.
The Tasmania map shows a cold minimum temperature anomaly area starting 4th June and running to the 10th. I am yet to dig into SE South Australian sites which look to have had some relatively colder minimums than Adelaide.
I made an error re Adelaide in that the min/max average of 12.05C in 2010-2019 should correctly be rounded to the odd 12.1C.
To make amends, I thought I’d check the CSIR Meteorological journal for all three locations mentioned in this post (Adelaide, Cooma, Canberra) to see how they stack up again recent temperatures …
Adelaide June
1857-1931 : Min 8.2C / Max 15.8C / Mean 12.0C
BoM long-term : Min 8.1C / Max 16.1C / Mean 12.1C
2010-2019 : Min 7.9C / Max 16.2C / Mean 12.1C
Cooma June
1866-1931 : Min -0.4C / Max 11.4C / Mean 5.5C
BoM long-term : Min -1.1C / Max 10.7C / Mean 4.8C
2010-2019 : Min -1.0C / Max 10.2C / Mean 4.6C
Canberra June
1917-1931 : Min 1.6C / Max 11.9C / Mean 6.7C
BoM long-term : Min 1.1C / Max 13.4C / Mean 7.3C
2010-2019 : Min 0.9C / Max 13.4C / Mean 7.2C
So put all three together and you get:
Pre-1931 : Min 3.1C / Max 13.0C / Mean 8.1C
BoM long-term : Min 2.7C / Max 13.4C / Mean 8.1C
2010-2019 : Min 2.6C / Max 13.3C / Mean 7.9C
So if the temperature averages collated by the CSIR are accurate, their mean is 0.2C cooler now than before 1931.
Any warming bias caused by pre-Stevenson screens might be offset against the increasing UHI since Stevenson screens.
The BoM’s CDO RAW minimum temperatures are roughly in agreement with the CSIR figures …
Adelaide West Terrace 1887-1978 : 8.4C
Adelaide Kent Town 1977-2019 : 8.1C
Cooma Lambie St 1858-1956 : -0.4
Cooma Airport 1992-2019 : -1.1C
Canberra Acton 1914-1939 : 1.4C
Canberra Airport 2009-2019 : 1.1C
Adelaide, Cooma, Canberra minima
Early stations : 3.1C
Current stations : 2.7C
The collective average June rainfall of Adelaide, Cooma and Canberra was …
Pre-1931 : 54.6mm
2010-2019 : 57.9mm
The 2010-2019 rainfall average is somewhat biased by a very wet 2016 June, but I’m sure there were a few times June was equally or more wet in the 70 years before 1931.
The trends suggest very cold minima at the three locations shouldn’t be a surprise as their nights are colder than they used to be.
A bit OT but relates to long term regional climatic change predictions “guesses”.
The ABC was hard at it during Landline yesterday, beating the climate change alarm drum with “Climate Atlas: Charting the weather in wine regions”. Some real gems such as, in the next few decades the Riverland region of SA will be “off the charts” with a temperature rise of 2.8 C:
www.abc.net.au/landline/climate-atlas:-charting-the-weather-in-wine-regions/12352920
The Landline segment apparently based on information from “Australia’s Wine Future:
A Climate Atlas” the result of “A three-year project with the University of Tasmania brought together an extensive, multi-disciplinary research team to consider the impact of seasonal climate variability and longer-term climate trends on the wine sector in Australia.”
www.wineaustralia.com/growing-making/environment-and-climate/climate-atlas
@Chris Gillham:
You have to factor in that the (old) West Terrace site was fairly open, with parkland on the prevailing wind direction (~70%).
The Kent Town site was about 1.5-2 grass tennis courts in size, surrounded with taller buildings and with a trafficked bitumen road on the other side of the concrete footpath. In the middle of a light industrial come commercial suburb.
Chris.
‘Any warming bias caused by pre-Stevenson screens might be offset against the increasing UHI since Stevenson screens.’
And also the one-second response time of the e-thermometers.
Re Graeme No.3 17th June [You have to factor in that the (old) West Terrace site was fairly open, with parkland on the prevailing wind direction] Rather than think about a relatively tiny area of park – I put more weight on the century scale expansion of Adelaide suburbs – all adding to UHI – and winds wafting from wherever being warmed before encountering any weather station – incl West Terrace.