This article from the Perth newspaper “The Sunday Times” 24th Feb 2013 says it with crystal clarity in the first paragraph.
But what did reality look like ? Well Perth Metro daytimes were 1.7° under normal and nights were 0.5° under. I think the blue shading here conveys that we are not dealing with sweltering heat.
The actual Perth district daily max and min temperatures for March 2013 can be seen here – and I have saved a large copy.
I wonder if The Sunday Times would listen to being told about this BoM failure.
The point should be made that Perth Metro’s max on Thursday 14 March was a system quirk in that the highest temperature from midnight to midnight was 19.7C, not 24.4C as recorded. The max happened just before 9am on the following day, Friday 15 March. About seven hour later around 4pm on 15 March, Perth Metro got to a max of 29.2C, accurately recorded by the BoM, but it means the Friday effectively scored two maxima.
Technically wrong but in reality 100% correct, the actual maximum on 14 March was 19.7C just after 6am, meaning the monthly average max was 27.8C, not 28.0C, and Perth Metro’s average daytime max in March was 1.9C below normal, not 1.7C. As such, it was the equal second coldest March recorded at Perth Metro and 0.2C below the Perth Regional Office mean from 1897 to 1992 atop Mt Eliza. Perth Regional was a cooler max location, maybe because of elevation, river proximity, wind exposure or a combination of the three, but had a warmer March in 1898, 1902, 1904, 1906, 1907, 1910, etc.
At 19.7C, 14 March 2013 was actually the fourth coldest early March day in Perth records since 1897, but that statistic will never appear. If you want to see history as it won’t be recorded, www.waclimate.net/imgs/14-mar-2013-perth.gif is a scan of weather reports from the Friday morning’s newspaper.
Perth Airport 9021 didn’t list a 14 March max on the BoM tables for at least a few days thereafter, but I’ve just checked and a temp has appeared showing an airport top of exactly 23.0C on 14 March. So the airport max was 1.4C cooler than Metro on that day, which is odd because the airport is normally warmer. For example, the previous day 13 March was 28.8C at 9021 and 28.2C at 9225. The following day 15 March was 29.7C at 9021 and 29.2C at 9225. The half hourly records are no longer available but I’ll betcha 23.0C happened at Perth Airport sometime on the Friday morning just before 9am.
Within 60km surrounding stations max on 14 March, nearest from top:
Swanbourne 24.4C
Gosnells 29.0C
Bickley 19.8C
Cunderdin 22.3C
Jandakot 24.4C
Pearce 24.4C
Medina 25.0C
Garden Island 23.6C
Rottnest Island 22.9C
Gingin 24.4C
Karnet 20.4C
Apart from 24.4C being a popular max that day, the Gosnells result also rings an alarm bell that many BoM station records around Perth on 14 March are unreliable. e.g. out of 6,706 days of temp recordings, it’s the 16th biggest ever difference in max between Gosnells and Bickley. I suspect Bickley is the only station above with max that actually happened on the Thursday rather than the Friday.
The 24 hour readings to 9am might be how the cookie crumbles but with one very cold day causing a .2C exaggerated and artificial warming of a capital city’s average monthly max, it’s a good example of how unreliable the temperature records can be, old and new.
On the 14th it rained from early morning to the evening,
www.perthnow.com.au/news/rain-rain-glorious-rain-hits-metro-area/story-e6frg12l-1226597401738
yet the BoM records the rain as being on the 15th.
www.bom.gov.au/climate/dwo/201303/html/IDCJDW6111.201303.shtml
I assume this is due to their practice of recording from 9am to 9am.
The rain on the 14th came in NW/SE oriented bands from the northwest. How long a location was under one of these bands would affect temperatures, and substantial differences between different Perth metro locations doesn’t surprise me. Plus a few showers the following morning before 9am would also have produced temperature differences between locations.
Warwick
Aren’t you confusing March with Autumn? Also, the person from the bom said 60% chance of Autumn being hotter. Isn’t that a 40% chance it will be cooler?
Or are you suggesting that there is a conspiracy???