Wednesday, 31 March 2010 - Monthly Climate Summary for Perth - Product code IDCKGC11L0

Perth in March 2010: A dry spell ended by a wild storm

• Above average rainfall
• Above average mean maximum temperature
• Above average mean minimum temperature
• A severe storm in Perth on the 22nd caused significant damage

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Rainfall

March rainfall across the Perth metropolitan area was above average, though rainfall totals were largely the result of one storm event toward the end of the month. The Perth region didn't register any significant rainfall for the first 21 days of March, following on from one of the driest summers on record as Perth Airport recorded 122 days without measurable rainfall, easily its longest dry spell in 66 years of rainfall recording. Although there were some showers on the 21st, mainly in the hills, severe storms swept through the Perth metropolitan area on the afternoon of Monday the 22nd, bringing the first significant rainfall to Perth since the 19th November 2009. The storm was considered to be one of the worst storms in Perth's history in terms of power outages and damage, caused mainly by large hail (up to 6 cm) and flash flooding. The highest daily rainfall total recorded in Perth during the event was 66.8 mm at Wanneroo DAFWA, whilst Jarrahdale recorded 57.2 mm. Perth Airport (42.2 mm) and Gosnells (53.0 mm) reported their highest daily March rainfall on record as a result of the storms, whilst Perth Metro registered 40.2 mm in the 24 hours to 9am on the 23rd, its fifth highest March daily rainfall since records began in 1876. For more details of the severe thunderstorms in Perth, please read the storm summary.

Perth Metro recorded 40.4 mm of rainfall on 2 days in March, compared with the average of 19.4 mm on about 5 days. This is Perth Metro's wettest March since 52.2 mm was recorded in March 2005. Historically, March rainfall in Perth has ranged from nil on 6 occasions, to 145.2 mm in 1934. Last March, Perth Metro registered 6.8 mm of rainfall on 6 days.

Maximum temperature

Mean maximum temperatures for March 2010 were above average across the Perth metropolitan area. Means were approximately 1 °C above average for most sites, and Swanbourne recorded its hottest March in 16 years of record. As is typical for March, temperatures in the first half of the month were much higher than during the second half of the month.

The first two days of March saw much of Perth in a heatwave (three or more days with daily maximum temperature over 35°C) that commenced on the 24th February. This was followed by a cooler change but hot days returned toward the middle of the month. Daily maximum temperatures exceeded 40°C at inland Perth sites on the 12th, with the highest temperature of 42.0°C in the metropolitan area being recorded at Medina Research Centre. The 41.0°C recorded at Perth Metro was the ninth hottest March day since records commenced in 1897. Daily maxima across the Perth area ranged from 42.0°C at Medina Research Centre on the 12th to 21.6°C at Garden Island on the 28th.

Perth Metro's mean daily maximum temperature in March 2010 was 30.2°C, which is near the average of 29.4°C, and was Perth Metro's hottest March since 2007. Daily maxima ranged from 41.0°C on the 12th, Perth Metro's hottest March day for three years since it's hottest ever March day on record of 42.4°C on 7th March 2007, to 23.2°C on the 27th.

Minimum temperature

Mean daily minimum temperatures for March 2010 were above average across the Perth metropolitan area, with most sites recording means 1 °C to 2 °C above normal. Daily minima across Perth in March ranged from 28.8 °C at Swanbourne on the 12th, to 10.0 °C at Bickley on the 5th and Pearce on the 31st.

Perth experienced an unusually hot March night on the 12th as minima at most sites exceeded 25 °C and many metropolitan sites broke March records (see records below). Swanbourne's 28.8 °C was the hottest March night in its 16 years of record, and the highest minimum recorded in Perth on the 12th, whilst Perth Metro's 28.1 °C was the second hottest March night on its 113 years of record.

Perth Metro's mean minimum temperature in March was 18.1 °C, well above the long-term average of 16.4 °C, and Perth's warmest March in terms of minimum temperatures since a mean of 18.4 °C was recorded in 2005. Daily minima ranged from the uncomfortable 28.1°C on the 12th to 13.1°C on the 20th.

Wind

Inland sites as well as the coastal plain experienced more frequent and stronger north-easterly winds in the morning, whilst afternoon sea breezes were close to normal. The daily highest wind gust of 120 km/h was recorded at Ocean Reef on the 22nd, when the severe storms swept through the metropolitan area.

Other Phenomena

Perth recorded sunshine of 9.0 hours, compared to the long-term average of 9.5 hours.

etails Extremes Records Summaries Important notes the top

Details Extremes Records Summaries Important notes the top

Details Extremes Records Summaries Important notes the top

Daily rainfall

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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