Thursday, 31 May 2012 - Seasonal Climate Summary for Perth - Product code IDCKGC21L0

Perth in autumn 2012: A warm dry autumn

• Rainfall: Below average for most sites.
• Maximum temperature: Above average
• Minimum temperature: Near average

Details Extremes Records Summaries Important notes the top

Rainfall

Rainfall across the Perth metropolitan area during autumn 2012 was below average for most sites, apart from Medina, Swanbourne, and Garden Island, which saw near average rainfall. Autumn rainfall totals were generally in the 80 mm to 140 mm range; while Pearce RAAF received the lowest autumn rainfall in the Perth area with 72.4 mm. The dry autumn was primarily due to a very dry March, where most sites reported less than 1 mm for the month, and well below average rainfall in May.

Significant rainfall events during autumn 2012 in Perth:

• A low pressure system brought moderate to heavy rainfall to the Perth area on 28 and 29 April, with totals mostly in the 20 mm to 30 mm range and isolated falls of up to 60 mm. The daily rainfall total at Swanbourne of 56.2 mm in the 24 hours to 9am on the 29th was the highest daily total of the season in the Perth area, and the second wettest April day for the site.
• A low and trough brought moderate rainfall in the Perth area between 3 and 6 May, with totals in the 20 to 40 mm range.

Perth Metro recorded 118.4 mm of rainfall on 17 rain days during autumn 2012, which was well below the average of 181.6 mm. Rainfall totals at Perth Metro for individual months this autumn were: March 0.2 mm (average 19.4 mm), April 69.2 mm (average 43.9 mm), May 49.0 mm (average 117.3 mm).

Maximum temperature

Mean daily maximum temperatures for autumn 2012 were generally above average; though some sites in the south and in the hills saw near average daily temperatures. Mean daily maxima for the season were in the mid-to-high twenties.

Autumn 2012 began with heatwave conditions (3 or more consecutive days of daily maximum temperature of 35 °C or higher) in the first half of March, and the daily maximum temperature of 41.9 °C at Gosnells City on 11 March was the highest temperature in the Perth area during autumn. The coldest day for autumn 2012 occurred on 9 May with maxima generally below twenty across the Perth metropolitan area as Bickley recorded a maximum of 16.5 °C.

Perth Metro's mean daily maximum temperature for autumn 2012 was 27.0 °C, 1.1°C above average and the equal third warmest autumn on record with 2009. Last autumn, Perth Metro observed its hottest autumn on record with a mean daily maximum temperature of 27.5 °C. The lowest daily maximum at Perth Metro during autumn 2012 was a mild 19.6 °C, the only sub-20 °C day for the season. Thus Perth Metro observed its lowest number of sub-20 °C days in autumn since records began in 1897, passing the previous record of two sub-20 °C days in 2011. The highest daily maximum during autumn at Perth Metro was a very hot 41.1 °C on 11 March, the hottest March day since the record for March at Perth Metro was set at 42.4 °C on 7 March 2007.

Minimum temperature

Mean daily minimum temperatures during autumn 2012 were near average across the Perth region, with mean daily minima in the low-to-mid teens.

Cold nights were experienced during the latter part of May due to a strong high in the Bight, with Jandakot and Gosnells City observing their coldest autumn night on record on the 25th. The daily minimum temperature of -0.6 °C at Jandakot Aerodrome on the 25 May broke the Jandakot record of -0.1 °C set on 15 May 2010 and was also the lowest temperature in the Perth area for the season. Perth Metro observed a minimum temperature of 1.3 °C on the 25th, which is the lowest autumn minimum temperature observed at the Mt Lawley site since records commenced in 1994, breaking the record of 2.4 °C on 27 May 2004, and also the equal coldest May night observed at any of the past official Perth Metro sites (commencing in 1897), equal with the 1.3 °C observed on 11 May 1914.

Perth Metro's mean daily minimum temperature for autumn 2012 was 13.6 °C, equal with the average. Daily minima across autumn ranged from a very cold 1.3 °C on 25 May to a warm 20.9 °C on 4 April.

Wind and Sunshine

Perth’s mean daily autumn sunshine was 8.7 hours in 2012, which was the equal fourth sunniest autumn on record with 1994 (sunshine records commenced in 1898). The sunniest autumn on record in Perth was last year (2011) with 9.2 hours of sunshine per day, whilst the average is 8.3.

remes Records Summaries Important notes the top

Extremes Records Summaries Important notes the top

Extremes Records Summaries Important notes the top