Monday, 2 November 2015 - Monthly Climate Summary for Perth - Product code IDCKGC11L0

Perth in October 2015: Warmest October on record

It was the warmest October on record for many sites in the Perth metropolitan area. Daytime temperatures were 2 °C to 5 °C warmer than normal and most sites observed their highest mean maximum temperature in October on record. Overnight temperatures were 1 °C to 3 °C above the long-term average and a few sites saw their highest mean minimum temperature in October on record. Rainfall in October 2015 was below to near average.

• Warmest daytime temperatures in October on record for Perth coastal plain and hills sites, including Perth Metro
• Mildest overnight temperatures in October on record for the coastal, offshore island and hills sites
• Below to near average rainfall

Across the Perth area, rainfall in October 2015 ranged from 20 mm to 50 mm across the coastal plain and on the offshore Islands, to 60 mm to 70 mm in the hills, and totals in the coastal plain sites were 40% to 60% below the long–term average. Rainfall was mostly light with some moderate falls reported on the 19th, 28th and 31st, though mostly in the Perth hills. A daily total of 40.2 mm at Jarradale on the 31st was the highest daily rainfall of the month in Perth. Perth Metro recorded 20.8 mm on nine rain days, which was the driest October for three years, since 2012, when 15.6 mm was recorded.

Mean maximum temperatures in October 2015 were 2 °C to 5 °C above normal across the Perth metropolitan area, and ranked as the warmest October mean maximum temperature on record for most sites. Mean maximum temperatures ranged from 22 °C to 23 °C on the offshore islands, 24 °C to 25 °C near the coast and in the hills, and 26 °C to 28 °C on the coastal plain. Days were mainly pleasantly mild to warm though there were some hot days and a few cool days during the month. Coastal plain sites observed between six and nine days with temperatures at or above 30 °C, their highest number of 30 °C days in October on record. The hottest day was the 9th for most sites and 36.4 °C at Pearce RAAF on the 9th was the highest temperature of the month in Perth. Karnet recorded the lowest maximum temperature of the month with 16.5 °C on the 5th.

Perth Metro recorded a mean maximum temperature of 26.8 °C, which was its warmest October since records commenced in 1897, exactly 1.0 °C warmer than the previous record set in October 1969. Eight days with temperatures at or above 30 °C were recorded at Perth Metro during the month, exceeding its previous record of six such days on October 2008. It was also unprecedented that a run of four days with temperatures at or above 32 °C was recorded between the 9th and 12th, the previous longest run being three from 19 to 21 October 2008.

Mean minimum temperatures in October 2015 ranged from 11 °C to 15 °C on the coastal plain and in the hills, to 16 °C on the offshore islands, and all sites were 1 °C to 3 °C above average. A few sites recorded their warmest October nights on record. Nights were mostly cool to mild with at least one third of the daily minimum temperatures being over 15 °C at some coastal plain sites during October. The mildest night was generally the 12th or the 28th, and Pearce RAAF reporting the highest overnight temperature of the month with 19.7 °C on the 12th. The coldest night was the 6th or 16th, with daily minima below 8 °C for inland coastal plain and hills sites. Perth Metro recorded a mean minimum temperature of 13.6 °C, which is the warmest October nights since 1982 when a mean minimum temperature of 13.6 °C was recorded. Perth Metro recorded 14 mild nights, where temperatures remained at or above 15 °C, during October, which was the highest number of mild nights in October in 117 years of record. The previous highest was 13 mild nights in October 1969.

Extremes Records Summaries Daily observations Important notes the top

Extremes Records Summaries Daily observations Important notes the top

Extremes Records Summaries Daily observations Important notes the top

Extremes Records Summaries Daily observations Important notes the top

Extremes Records Summaries Daily observations Important notes the top