Perth in autumn 2010

An average autumn for Perth

  • Near average rainfall.
  • Near average mean daily maximum temperature.
  • Near average mean daily minimum temperature.

Rainfall

Rainfall totals for autumn 2010 were generally in the 150 to 200 mm range which is close to average. The Perth region did not register any significant rainfall for the first 21 days of autumn, following one of the driest summers on record. Perth Airport recorded 122 days without measurable rainfall, easily its longest dry spell in 66 years of rainfall recording. Severe storms swept through the Perth metropolitan area on the afternoon of 22 March, bringing the first significant rainfall to Perth since 19 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 (and for autumn) was 66.8 mm at Wanneroo (DAFWA), whilst Jarrahdale recorded 57.2 mm. For more details of the severe thunderstorms in Perth, please read the storm summary.

Perth Metro recorded 154.0 mm on 15 days during autumn 2010 compared with the average of 188.3 mm on about 23 days. Rainfall totals for individual months this autumn were: March 40.4 mm (average 19.4 mm), April 25.0 mm (average 44.2 mm) and May 88.6 mm (average 117.7 mm). Last autumn, Perth Metro recorded 57.8 mm on 12 days, the second driest autumn on record. The driest autumn being 42.4 mm in 1983. The wettest day in autumn 2010 was the 40.2 mm recorded in the 24 hours to 9am on the 23rd of March, which occurred during the severe thunderstorms the previous day. It was Perth Metro's wettest March day for 39 years and ranked the fifth wettest March day on record. Perth Metro's wettest March day on record was 77.0 mm on the 9th March 1934.

Maximum temperature

Averaged over the three months of autumn 2010, maximum temperatures were near average in the Perth region. The first two days of autumn saw much of Perth in a heatwave (three or more days with daily maximum temperatures over 35C) that commenced on the 24th February. Daily maximum temperatures exceeded 40C at inland Perth sites on 12 March 2010, with the highest temperature of 42.0C in the metropolitan area being recorded at Medina Research Centre.

Perth Metro's mean daily maximum temperature in autumn 2010 was 25.6 °C, which was close to the average of 25.8 °C. It was the coolest autumn since the 25.4 °C in 2008. Daily maxima ranged from a cool 16.7 °C on the 13th of May to a very hot 41.0 °C on 12th March which was the hottest March day for three years. Autumn 2009 was the second warmest on record with 27.0 °C, the warmest autumn, being 27.2 °C in 1978.

Minimum temperature

Averaged over the three months of autumn 2010, minimum temperatures were also near average in the Perth region. An exceptionally warm night occurred on 12 March, with a number of sites breaking their highest March and autumn minimum temperature records. In contrast, Jandakot Aerodrome and Gosnells City recorded their coolest overnight autumn minimum temperature on 15 May 2010

Perth Metro's mean daily minimum temperature in autumn 2010 was 13.6 °C, which equals the average of 13.6 °C. Daily minima ranged from a cold 2.5 °C on 15th May to a hot 28.1 °C on 12th March which was Perth Metro's hottest March night since the record of 28.3 °C on the 2nd March 1934.

Wind & sunshine

Ocean Reef recorded the highest wind gust for autumn with 120 km/h recorded during the severe thunderstorms of 22 March, while Jandakot Aerodrome recorded 96 km/h in the same event. Rottnest Island was the only other site to observe severe gusts for autumn 2010.

Average daily autumn sunshine hours at Perth Airport was 8.2 hours which equals the average of 8.2 hours.

Further information

Media
(03) 9669 4057
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Extremes in autumn 2010
Hottest day 42.0 °C at Medina Research Centre on 12 Mar
Warmest days on average 27.0 °C at Pearce RAAF
Coolest days on average 23.1 °C at Rottnest Island
Coldest day 12.9 °C at Bickley on 13 May
Coldest night -0.1 °C at Jandakot Aero on 15 May
Coolest nights on average 11.7 °C at Jandakot Aero
Warmest nights on average 16.9 °C at Rottnest Island
Warmest night 28.8 °C at Swanbourne on 12 Mar
Wettest overall 207.6 mm at Jarrahdale
Wettest day 66.8 mm at Wanneroo (DAFWA) on 23 Mar
57.2 mm at Jarrahdale on 23 Mar
Highest wind gust 120 km/h at Ocean Reef on 22 Mar



Record highest autumn daily minimum temperature
Highest daily minimum
temperature
in autumn 2010 (°C)
Previous highest
for autumn
Years of
record
Average for
autumn
Perth Airport 28.6 on 12 Mar 26.2 on 9 Mar 1996 66 13.1
Pearce RAAF 28.1 on 12 Mar 28.0 on 8 Mar 2007 56 13.4
Medina Research Centre 27.7 on 12 Mar 25.5 on 9 Mar 2000 25 13.2
Jandakot Aero 27.9 on 12 Mar 25.3 on 6 Mar 1990 20 12.3
Bickley 24.3 on 12 Mar 24.0 on 9 Mar 2000 17 12.3
Swanbourne 28.8 on 12 Mar 26.7 on 8 Mar 2007 17 15.0



Record lowest autumn temperature
Lowest temperature
in autumn 2010 (°C)
Previous lowest
for autumn
Years of
record
Average for
autumn
Jandakot Aero -0.1 on 15 May 0.4 on 25 May 2006 20 12.3
Gosnells City 4.0 on 15 May 4.1 on 27 May 2004 18 14.5



Summary statistics for autumn 2010
Maximum temperatures
for autumn
(°C)
Minimum temperatures
for autumn
(°C)
Rainfall
for autumn
(millimetres)
Mean for
autumn
2010
Diff
from
average
Highest for
autumn
2010
Mean for
autumn
2010
Diff
from
average
Lowest for
autumn
2010
Total for
autumn
2010
Average
for
autumn
Rank of
autumn
2010
Fraction of
autumn
average
Bickley 23.5 -0.1 38.5 1 Mar 12.6 +0.3 5.5 14 May 177.4 211.0 average 84%
Champion Lakes 25.4   39.1 12 Mar 14.9   5.2 15 May 156.6
Garden Island HSF 23.7   38.8 12 Mar 15.8   8.9 8 May 118.4
Gosnells City 26.7 +0.3 41.5 12 Mar 14.2 -0.3 4.0 15 May 179.5 167.2 average 107%
Jandakot Aero 26.0 +0.3 40.8 12 Mar 11.7 -0.6 -0.1 15 May 177.4 167.0 average 106%
Medina Research Centre 25.9 +0.3 42.0 12 Mar 13.2 0.0 2.1 15 May 148.2 161.6 average 92%
Pearce RAAF 27.0 +0.8 41.2 12 Mar 12.7 -0.7 0.9 15 May 90.6 136.3 low 66%
Perth Airport 26.4 +0.8 41.1 12 Mar 12.9 -0.2 1.1 15 May 152.4 158.1 average 96%
Perth Metro* 25.6 -0.2 41.0 12 Mar 13.6 0.0 2.5 15 May 154.0 188.3 average 82%
Rottnest Island 23.1 -0.5 37.5 11 Mar 16.9 -0.1 9.5 27 May 115.2 125.7 average 92%
Swanbourne 25.3 -0.1 39.8 12 Mar 14.7 -0.3 6.3 15 May 199.6 149.5 high 134%

Notes

This statement was prepared before all data for the period were available. This may affect some of the statistics presented.

A Seasonal Climate Summary is prepared to list the main features of the weather in Perth using the most timely and accurate information available on the date of publication; it will generally not be updated. Later information, including data that has had greater opportunity for quality control, will be presented in the Monthly Weather Review, usually published in the fourth week of the month.

This statement has been prepared based on information available at 1 pm on Monday 31 May 2010. Some checks have been made on the data, but it is possible that results will change as new information becomes available.

Averages are long-term means based on observations from all available years of record, which vary widely from site to site. They are not shown for sites with less than 10 years of record.
The median is sometimes more representative than the mean of long-term average rain.

The Rank indicates how rainfall this time compares with the climate record for the site, based on the decile ranking (very low rainfall is in decile 1, low in decile 2 or 3, average in decile 4 to 7, high in decile 8 or 9 and very high is in decile 10).
The Fraction of average shows how much rain has fallen this time as a percentage of the long-term mean.

Records in this summary are based on sites with at least 10 years of data.

*Official Perth observations have been recorded at several different sites with varying instrumentation over the years, and these changes can affect the continuity of the climate record. For the current Mt Lawley site, the most significant changes of this kind relate to temperature and rain days.

For that reason, current mean temperature and rain-day data quoted here are based only on readings from the Mt Lawley site, which commenced observations in 1993. Sunshine recordings are from Perth Airport and for similar reasons current means use only Perth Airport data, which commenced in 1993.

For PDF files of Perth Metro climate statistics for other months, please click here for extremes and here for averages.

Further information

Media
(03) 9669 4057
Enquiries