Tuesday, 31 August 2010 - Monthly Climate Summary for Perth - Product code IDCKGC21L0

Perth in August 2010: A dry month with many cold nights

• Very much below average rainfall across the Perth metropolitan area.
• Near average to above average mean maximum temperature
• Below to very much below average mean minimum temperature for most sites.

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Rainfall

Fewer than normal cold fronts passing across southwest WA in August resulted in below average rainfall for the Perth metropolitan area, with totals ranging from about 45 mm at Gosnells City to around 90 mm at Rottnest Island.

An unusually dry start to August ended when a strong cold front and low pressure system crossed the Perth region on the 12th bringing useful rainfall, as well as the highest daily falls for the month. Swanbourne recorded the highest daily rainfall in the Perth metropolitan area for August 2010 with 28.4 mm on the 12th, whilst two-day totals including the 12th and 13th were typically 30 to 40 mm across the metropolitan area. Several weaker fronts moved through Perth in the remainder of the month though daily falls were modest.

Perth Metro recorded 63.0 mm of rainfall on 8 rain days in August, which was the driest August since the 27.8 mm in 2008. Historically, August rainfall in Perth has ranged from 11.8 mm in 1902 to 318.3 mm in 1945.

The total rainfall for the eight months from January to August 2010 at Perth Metro was 410.6 mm recorded on 46 rain days, which was the driest January to August period since the 340.4 mm in 2006, and the fourth driest since records commenced in 1876. The average for the January to August period is 684.3 mm on about 76 rain days while the total for the same period last year was 482.0 mm on 71 days. Perth Metro also experienced its least number of rain days for the eight months (January to August) on record. The previous record low being 59 days in 1902.

Maximum temperature

Mean daily maximum temperatures in the Perth area during August 2010 were close to average or above average, ranging from 16.5 °C at Bickley to 20.1°C at Gosnells City. Perth Airport saw the largest departure from the mean with an August mean daily maximum temperature of 19.6 °C, 1.2 °C above the long-term average.

August 2010 started quite warm with most sites reporting maxima over 20 °C in the first 4 days of the month, and the warmest day in the Perth metropolitan area in August was 24.9 °C at Gosnells City on the 3rd. The coldest day for the month was 12.5 °C at Bickley on the 18th as cold southerly winds predominated.

Perth Metro's mean daily maximum temperature in August was 19.1 °C, which is close to the average of 18.8°C. Daily maxima ranged from a warm 24.1 °C on the 2nd, to a cold 14.3 °C on the 31st, which was the coldest day in August for 6 years.

Minimum temperature

Mean daily minimum temperatures were below to very much below average for much of the Perth area with overnight temperatures generally about 2 °C cooler than normal. Pearce RAAF's mean minimum temperature in August was 6.2 °C, breaking the previous record of 6.3 °C set in August 2001, whilst Gosnells also recorded its lowest August mean minimum temperature.

The coldest night recorded in the Perth metropolitan area in August was -0.4 °C at Jandakot Aerodrome on the 9th as a high moved over southern WA following the passage of a weak front near the WA south coast. The warmest night was 14.8 °C at Rottnest Island on the 2nd in a prevailing northwesterly flow.

Perth Metro's mean daily minimum temperature in August was 6.3 °C, which was the second coldest August for Perth Metro on record behind the 5.6 °C in 2008. Daily minima in August 2010 ranged from a mild 12.3 °C on the 12th, to a cold 1.4 °C on the 9th, the equal second coldest August night on record at Perth Metro. Perth Metro's coldest August temperature of 1.3 °C occurred on 21st August 2000.

Wind & sunshine

The highest wind gust recorded in the Perth metropolitan area in August was 98 km/h at Rottnest Island on the 11th as a cold front crossed Perth.

Perth recorded an average daily sunshine of 7.9 hours in August, which is the equal fourth sunniest August on record. The long-term average is 7.1 hours per day, whilst the sunniest August on record saw 8.5 hours per day in 2008.

Details Extremes Records Summaries Important notes the top

Details Extremes Records Summaries Important notes the top

Details Extremes Records Summaries Important notes the top

Most values are the precipitation in the 24 hours to 9 am on the day indicated. Days marked with »» are part of a longer accumulation, which is marked like this on the final day. Values over 100 mm have been rounded to the nearest whole millimetre. Days marked with - have a rainfall report of zero; days left blank have no rainfall report (which often indicates no rain fell).
This table is very wide; you may have to scroll sideways to see all the days, and you may need to set the paper to 'landscape' to print.

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