Western Australia in 2009: A very warm year

  • Second warmest year on record for WA in terms of mean maximum temperature.
  • Sixth warmest year on record for WA in terms of mean minimum temperature.
  • Near average rainfall for WA

Rainfall

WA annual rainfall in 2009 was below to very much below average in the far western Pilbara, western Gascoyne, eastern Interior, and a large part of the SWLD. Part of the Great Southern district recorded very much below average annual rainfall and Lake Grace recorded its lowest annual rainfall total in almost one hundred years of recording. In contrast, above to very much above average rainfall was experienced in parts of the northern and western Kimberley, as well as parts of the Pilbara. The statewide annual mean total was 328 mm, which is near the average annual total of 339 mm.

January: statewide rainfall was above average as Tropical Cyclone Dominic produced heavy rainfall and flooding in the west Pilbara, inland Gascoyne and Goldfields with some record high daily and monthly totals.

February: statewide rainfall was near average though tropical lows brought above average rainfall to much of the Kimberley and west Pilbara, and caused significant flooding in the Robe and Fortescue Rivers in mid-February.

Autumn: An early end to the wet season in the north in March and a lack of significant cold fronts in the south in April and May resulted in a dry autumn in much of WA. Many locations in the Southwest Land Division (SWLD) experienced their driest autumn on record. Kalbarri in the Central West district recorded its first rain for 2009 on 21 May after 169 rain free days that commenced in early December 2008.

Winter: Widespread rainfall in the SWLD from a number of strong cold fronts in early June was followed by a near average July and a dry August. Statewide winter rainfall was near average.

Spring: A promising start saw above average rainfall in large parts of the southern half of WA in September, however a dry October (5th driest October in the southwest), followed by an above average November for much of WA, resulted in a near average spring statewide.

December: Seasonally dry in much of the SWLD, but Severe Tropical Cyclone Laurence brought significant rainfall to parts of the north and west Kimberley and Pilbara regions, with some all-time rainfall records broken.

Maximum temperature

2009 was a very warm year with mean maximum temperatures above to very much above average across most parts of WA, although SWLD south coast districts and neighbouring parts of adjacent regions recorded mostly close to average temperatures. Only in parts of WA south coast districts were below average mean maxima recorded in 2009. Averaged across the state as a whole, the annual mean maximum temperature was 30.3°C, which is 1.0°C above the long term (1961-1990) average, and the 2nd warmest year on record for WA. The statewide mean maximum temperature for the three months October to December 2009 was the highest on record.

January: A warm start to the year across much of the state with a hot spell and record high temperatures for January in western parts.

February: Near average mean maximum temperatures.

Autumn: Warmer than normal mainly in the north and west.

Winter: A warm June and July in the north and an abnormally warm August (2nd warmest August on record) resulted in a well above average mean maximum temperature for winter for WA (7th warmest winter on record).

Spring: September saw cool conditions in the south (2nd coldest on record in the southwest) and hot in the north. A warmer than normal October across much of WA saw record high daily temperatures in the SWLD & Eucla, and November turned out to be abnormally warm for most of WA, especially in the eastern Interior and Eucla. Record high temperatures and a notable hot spell were registered in far eastern parts.

December: Very warm with the 3rd warmest December on record for WA.

Minimum temperature

Mean minimum temperatures were above to very much above average for much of WA, although western parts of WA were generally close to normal, and western parts of the Gascoyne, and the far west Pilbara recorded below average mean annual minima for 2009. Averaged across the state as a whole, the annual mean minimum temperature was 16.3°C, which is 0.6°C above the long term (1961-1990) average, and the 6th highest mean annual minimum temperature on record for WA.

January: The year started with an abnormally hot January, the 2nd hottest January on record in WA.

February: Above average mean minima were recorded across much of WA.

Autumn: A near average autumn was observed as a result of a near average March, a warmer than normal April, and a cooler than normal May.

Winter: Mostly near average mean minima in June, above average mean minima in July, and the 5th warmest August on record resulted in warmer than normal winter nights overall.

Spring: A warmer than normal spring was the result of a very warm September in the north, and a warm October and November in the southern half of the state.

December: Very warm with the 4th highest mean minimum temperature for WA for December on record.

Notable events

  • Tropical Cyclone Dominic crossing the northwest coast near Onslow in late January, bringing heavy rainfall and flooding along its path.
  • Two tropical lows crossing the Pilbara coast in mid-to-late February, bringing heavy rainfall and flooding to the Pilbara.
  • A maximum temperature of 39.7 ºC recorded at Wyndham Aerodrome, in the Kimberley district, on 31 August, being the second highest August temperature on record for WA and Australia.
  • Forrest in the Eucla district setting a new record hot spell for that location with 15 consecutive days with 35 °C, or above, between 6 and 15 November.
  • Severe Tropical Cyclone Laurence (category 5) crossing the Kimberley coast east of Koolan Island on 16 December and then the Pilbara coast near Mandora on the 21st, bringing destructive winds and heavy rainfall along its path. Daily rainfall of 402.0 mm at Napier Downs on 18 December was the 2nd highest December daily rainfall on record for WA.

Further information

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Extremes in 2009
Hottest day 49.0 °C at Emu Creek Station on 10 Jan
Warmest days on average 36.7 °C at Fitzroy Crossing Aero
Coolest days on average 19.6 °C at Albany
Coldest day 8.8 °C at Shannon on 29 Jun
Coldest night -4.3 °C at Eyre on 9 Sep
Coolest nights on average 8.2 °C at Collie East
Warmest nights on average 26.2 °C at Troughton Island
23.6 °C at Kuri Bay(mainland)
Warmest night 32.9 °C at Wittenoom on the 31st
Wettest overall 1962.7 mm at Kuri Bay
Driest overall 73.5 mm at Gascoyne Junction
Wettest day 402.0 mm at Napier Downs on 18 Dec
Highest wind gust

187 km/h at Troughton Island on 15 Dec
148 km/h at Wyndham Aero on 7 Jan (mainland)

Record highest daily rainfall
Highest daily rainfall
in 2009 (mm)
Previous annual
highest
Years of
record
Red Hill 230.8 on 17 Feb 170.9 on 30 Jan 1928 110
Kimberley Downs 310.6 on 18 Dec 260.0 on 13 Mar 1984 101
Warrawagine 244.5 on 22 Dec 190.4 on 15 Dec 1998 100
Napier Downs 402.0 on 18 Dec 255.8 on 28 Feb 1946 93
Beringarra 113.8 on 28 Jan 112.8 on 10 Mar 1926 92
Yalleen 300.0 on 17 Feb 167.0 on 8 Mar 2000 52
Lort River 118.0 on 28 Jan 115.4 on 11 Mar 2000 41
Pannawonica 244.6 on 17 Feb 228.0 on 25 Feb 1989 39



Record lowest total annual rainfall
Total rainfall
for 2009 (mm)
Previous annual
lowest
Years of
record
Annual
average
Lake Grace Comparison 187.0 196.4 in 2002 97 352.2




Record highest daily minimum temperature
Highest daily minimum
temperature
in 2009 (°C)
Previous annual
highest
Years of
record
Annual
average
Halls Creek Airport 31.8 on 9 Dec 31.6 on 15 Dec 1985 66 20.0
Eucla 30.2 on 26 Feb 29.5 on 24 Nov 1982 53 12.2
Balladonia 27.1 on 30 Dec 26.5 on 1 Nov 1981 45 9.8





Record lowest annual mean daily minimum temperature
Mean daily minimum
temperature
for 2009 (°C)
Previous annual
lowest
Years of
record
Annual
average
Jurien Bay 12.0 12.2 in 1971 39 13.0




Notes

This statement has been prepared based on information available at 9 am on Monday 4 January 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 30 years of record, as they cannot then be calculated reliably.
The median is sometimes more representative than the mean of long-term average rain.

Further information

Media
(03) 9669 4057
Enquiries