Perth in winter 2010: One of the driest winters on record

This statement was prepared before all data for the period were available. This may affect some of the statistics presented.
  • Lowest rainfall on record for several sites.
  • Near average mean daily maximum temperatures.
  • Very much below average mean daily minimum temperatures for most sites.

Rainfall

Rainfall in winter 2010 was very much below average across the Perth metropolitan area, and was the driest winter on record for several sites. The dry winter was a result of very much below average June rainfall, a slightly below average July, and a very much below average August.

Rainfall totals for winter ranged from 190.8 mm at Pearce RAAF to 312.4 mm at Jarrahdale, and both sites, along with several other mostly inland sites, registered their driest winter on record. The wettest day in winter 2010 was the 9th July when a strong cold front brought heavy rainfall to much of Perth, with 55.0 mm at Bickley on the 9th July being the highest daily fall recorded in the Perth Metropolitan area in winter.

Perth Metro recorded 256.4 mm on 30 days during winter 2010, which was the second driest winter on record, the driest being 230.0 mm on 35 days in 2006. Rainfall totals for individual months this winter were: June 51.4 mm (average 176.7 mm), July 142.0 mm (average 169.9 mm), August 63.0 mm (average 134.1 mm).

Perth Metro recorded its least number of rain days for winter on record with 30. The previous record was 35 rain days in 1902 and 2006.

Maximum temperature

Averaged over the three months of winter 2010, maximum temperatures were near average in the Perth region, ranging from about 16 to 19 °C. Most sites recorded mean maxima for winter within 0.5 °C of their long-term mean.

The coldest day for winter coincided with the wettest day, with the daily maximum temperature on the 9th July registering only 9.8 °C at Bickley. The warmest day for winter was the 13th June when Gosnells City recorded the highest daily maximum temperature of 25.0 °C.

Perth Metro's mean daily maximum temperature in winter 2010 was 18.8 °C, which equalled the average. Daily maxima across winter ranged from a cool 13.3 °C on the 9th of July, which was Perth Metro's coldest July day for seven years, since the 12.5 °C on the 14th July 2003, to a warm 24.6 °C on 13th June.

Minimum temperature

Averaged over the three months of winter 2010, minimum temperatures were very much below average for most sites. Perth Metro, Pearce RAAF and Gosnells City registered their lowest mean minimum temperature for winter on record. A significant run of cold nights (nights with minima less than 5 °C) occurred during June and July across the Perth metropolitan area. Perth Airport recorded 15 consecutive cold nights from the 24th June to the 8th July, its longest run of cold nights in 66 years of record, and easily passing the previous record of 11 consecutive cold nights in winter 1990.

The coldest night for winter was the 26th June when Jandakot Aerodrome registered -2.5 °C. The warmest night during winter was the 14th June as daily minima ranged from 11 to 14 °C across the Perth metropolitan area, and Rottnest Island recorded a minimum of 16.5 °C.

Perth Metro's mean daily minimum temperature in winter 2010 was 6.4 °C, well below the average of 8.2 °C. Daily minima across winter ranged from a cold -0.6°C on the 26th June, Perth Metro's second coldest night on record, and just above the record of -0.7 °C on the 17th June 2006, to a mild 14.0 °C on 15th June. Perth Metro recorded 37 cold nights (nights with minima less than 5 °C) during winter 2010, whch equals the record for the Perth Metro (Mt Lawley) site set in 2001. This includes a record run of 15 consecutive cold nights from the 24th June to the 8th July.

Wind & sunshine

Rottnest Island recorded the highest wind gust for winter with 104 km/h on the 11th July when a strong cold front crossed the Perth area.

Average daily winter sunshine at Perth was 7.2 hours, the equal sunniest winter on record, along with 2001, since records commenced in 1898. The previous record was 7.1 hours per day in 2006. The average for winter is of 6.4 hours per day.

Further information

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Extremes in winter 2010
Hottest day 25.0 °C at Gosnells City on 13 Jun
Warmest days on average 19.4 °C at Gosnells City
Coolest days on average 15.8 °C at Bickley
Coldest day 9.8 °C at Bickley on 9 Jul
Coldest night -2.5 °C at Jandakot Aero on 26 Jun
Coolest nights on average 4.8 °C at Jandakot Aero
Warmest nights on average 12.3 °C at Rottnest Island
Warmest night 16.5 °C at Rottnest Island on 14 Jun
Wettest overall 312.4 mm at Jarrahdale
Wettest day 55.0 mm at Bickley on 9 Jul
Highest wind gust 104 km/h at Rottnest Island on 11 Jul

Record lowest total winter rainfall
Total rainfall
for winter 2010 (mm)
Previous lowest
for winter
Years of
record
Average for
winter
Jarrahdale 312.4 343.4 in 1976 125 641.0
Pearce RAAF 190.8 233.1 in 1971 55 377.2
Gosnells City 251.2 288.8 in 2006 47 462.3
Bickley 299.6 388.6 in 1989 42 594.6
Jandakot Aero 247.0 284.6 in 2006 35 464.1
Medina Research Centre 259.6 284.1 in 2006 28 414.5




Record lowest winter mean daily minimum temperature
Mean daily minimum
temperature
for winter 2010 (°C)
Previous lowest
for winter
Years of
record
Average for
winter
Pearce RAAF 6.3 6.6 in 2001 49 8.7
Gosnells City 7.3 7.5 in 2001 16 9.1
Perth Metro 6.4 6.6 in 2001 16 8.1



Summary statistics for winter 2010
Maximum temperatures
for winter
(°C)
Minimum temperatures
for winter
(°C)
Rainfall
for winter
(millimetres)
Mean for
winter
2010
Diff
from
average
Highest for
winter
2010
Mean for
winter
2010
Diff
from
average
Lowest for
winter
2010
Total for
winter
2010
Average
for
winter
Rank of
winter
2010
Fraction of
winter
average
Bickley 15.8 +0.2 21.8 28 Aug 7.1 -0.4 2.4 25 Jun 299.6 594.6 lowest 50%
Champion Lakes 18.2   24.0 3 Aug 8.4   2.7 4 Jul 226.8
Garden Island HSF 17.9   23.0 13 Jun 10.4   5.8 25 Jun 222.6
Gosnells City 19.4 +0.3 25.0 13 Jun 7.3 -1.8 0.5 26 Jun 251.2 462.3 lowest 54%
Jandakot Aero 18.9 +0.5 24.3 13 Jun 4.8 -2.3 -2.5 26 Jun 247.0 464.1 lowest 53%
Medina Research Centre 19.1 +0.3 24.7 13 Jun 6.7 -1.8 0.0 26 Jun 259.6 414.5 lowest 63%
Pearce RAAF 18.7 +0.4 24.7 28 Aug 6.3 -2.4 -1.9 4 Jul 190.8 377.2 lowest 51%
Perth Airport 19.1 +0.7 24.7 28 Aug 6.4 -2.0 -1.0 3 Jul 237.6 438.7 v low 54%
Perth Metro 18.8 0.0 24.6 13 Jun 6.4 -1.8 -0.6 26 Jun 256.4 480.7 v low 53%
Rottnest Island 17.7 -0.3 22.4 13 Jun 12.3 -0.3 7.9 10 Jul 252.2 307.7 low 82%
Swanbourne 18.9 +0.2 24.3 13 Jun 8.8 -1.3 2.9 25 Jun 284.2 391.3 v low 73%

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 12 pm on Tuesday 31 August 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, as they cannot then be calculated reliably.
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