Monday, 5 January 2009 - Annual Climate Summary for Western Australia - Product code IDCKGC21R0

Western Australia in 2008
A warm year for WA

Summary

  • WA statewide annual rainfall - near average
  • Above average mean maximum temperature for WA
  • Above average mean minimum temperature for WA

 

Rainfall

Annual rainfall in 2008 was near average for much of WA. Above to very much above average totals were recorded in the north Kimberley, and in the west Pilbara and west Gascoyne, and some sites in these regions registered their highest annual rainfall totals on record. Conversely, below to very much below average rainfall was recorded in parts of the Interior and adjacent Pilbara and Goldfields. The statewide mean annual rainfall total was 379 mm, close to the long-term WA annual average of 351 mm.

Rainfall across WA in January was near average, but an active monsoon and a series of middle level troughs brought above average falls to a large part of WA in February, with some locations receiving their highest February rainfall on record. February was easily the wettest month for WA in 2008 in terms of total rainfall recorded across the state. A dry autumn was experienced in central and eastern parts of WA, contrasting with above average autumn rainfall in the southwest corner, and in the west Pilbara and west Gascoyne, largely the result of a series of cyclones and tropical lows in March and April. May was the fourth driest May on record for WA with below to very much below average rainfall experienced across almost all of the state.

Dry conditions continued in winter in the southwest of WA, due to below to very much below average rainfall in June and August, whilst an unseasonal wet winter was experienced in the Kimberley and adjacent areas. Spring started with near average falls in September and October but finished with an exceptionally wet November, the third wettest on record for WA, resulting in a wet spring overall. A deep surface trough produced record highest daily and monthly rainfall for November in parts of the South Coastal district on the 21st. Albany and Peaceful Bay both recorded daily totals over 100 mm, which are in the highest November daily falls in SW WA on record, and the total for Albany was its highest daily fall on record. The year ended with further significant rainfall events in December in the Kimberley, with the passage of Tropical Cyclone Billy, as well as in the Pilbara, Interior and in south coast districts. Some falls in SW WA were close to the record December daily rainfall for the region, whilst as a result of TC Billy, Wyndham reported 254.0 mm to 9am on the 21st, its highest daily rainfall on record for December, and the highest daily rainfall recorded in WA for 2008.

Temperature

2008 was a warm year for most parts of WA with mean temperatures above to very much above average across a large proportion of the state . Only parts of the north and east Kimberley and west Gascoyne recorded below average mean temperatures. Averaged across the state as a whole, the annual mean temperature was 22.9°C, which is 0.4°C above the long term (1961-1990) average and the fifteenth warmest year on record since comparable records commenced in 1910.

Maximum temperatures across WA in 2008 showed a similar warm bias to mean temperatures. Above to very much above average maximum temperatures were recorded across a large proportion of the state with only small parts of the state near the south coast recording below average annual mean maximum temperatures. Averaged across the state, the mean maximum temperature for 2008 was 29.8°C, which is 0.5°C above the long term (1961-1990) average, and the thirteenth warmest year on record since comparable records commenced in 1910.

Mean minimum temperatures across the state were generally average to above average in 2008, with the Eucla and parts of neighbouring districts very much above average. Much of the north and east Kimberley, and parts of the northern Interior, west Gascoyne and far west Pilbara, saw below average annual minima. Averaged across the state, the annual mean minimum temperature was 15.9°C, 0.2°C above the 1961-90 average.

January 2008 was the hottest January on record for WA in terms of both maximum and minimum temperatures, and several sites in the Pilbara and Gascoyne registered their all-time highest temperature during the month. This was contrasted in February by below average mean maxima across much of WA. Very cool maximum temperatures were recorded in the Central West, Central Wheat Belt and Goldfields, with Kalgoorlie registering its three coldest February days on record between the19th and 21st as a result of cloudband development associated with the decay of Tropical Cyclone Nicholas near the WA west coast.

Autumn commenced with an unprecendented hot spell in the Eucla district. Records were broken as Eucla and Forrest experienced prolonged heat waves (Eucla - 6 consecutive days over 40ºC; Forrest - 13 consecutive days over 35ºC) in the first half of the month, with an extreme spell of hot weather also affecting neighbouring South Australia. Despite this, March and April saw close to normal temperatures averaged across WA, however above average maxima across most of WA in May 2008 produced the fourth warmest May on record for the state.

Winter had a warm start in June and July with mean maxima generally above average, however, it ended with a cold dry August with maxima and minima mostly below average across WA. Thus overall, winter was close to normal for temperatures across most of WA. September and October were warmer than normal for most of WA, but November 2008 saw the third lowest mean maximum temperature for November for WA on record, and below average minima across southern and central parts of the state. Generally average or cooler than normal conditions persisted into December for most of WA.

Notable events

  • The hottest January on record for WA with very hot conditions in inland and northern parts where temperatures over 49ºC were reported and some sites in the Pilbara and Gascoyne recorded their highest ever temperature.
  • Tropical Cyclone Nicholas crossing the WA west coast near Coral Bay in late February, bringing heavy rainfall to the Gascoyne region.
  • A sequence of tropical lows affecting the west Pilbara and Gascoyne coast in February, March and April bringing very much above average rainfall to these regions and contributed significantly to some sites recording annual rainfall records.
  • A minimum temperature of -7.2ºC recorded at Eyre, in the Eucla district, on 17 August, setting an all-time lowest temperature record for WA.
  • Tropical Cyclone Billy crossing the WA Kimberley coast near Wyndham in the second half of December and bringing record rainfall to Wyndham, before weakening into a tropical low, tracking across the north Kimberley and bringing heavy rainfall, then moving off the coast near Kuri Bay and reforming into a tropical cyclone, tracking west of WA and eventually dissipatinge over the Indian Ocean.

Further information

Western Australia Climate Services Centre
Bureau of Meteorology
Phone (08) 9263 2222
Email climate.wa@bom.gov.au

Extremes

Hottest day
Highest temperature
49.2 °C at Onslow on 11 Jan
Warmest days on average
Highest mean daily maximum temperature
36.2 °C at Fitzroy Crossing Aero
Coolest days on average
Lowest mean daily maximum temperature
19.5 °C at Albany
Coldest day
Lowest daily maximum temperature
9.4 °C at Katanning Comparison on 21 Sep
Coldest night
Lowest temperature
-7.2 °C at Eyre on 17 Aug
Coolest nights on average
Lowest mean daily minimum temperature
7.9 °C at Collie East
Warmest nights on average
Highest mean daily minimum temperature
25.4 °C at Troughton Island
Warmest night
Highest daily minimum temperature
34.2 °C at Marble Bar on 21 Jan
Wettest overall
Highest total rainfall
1935.2 mm at Kuri Bay
Wettest day
Highest daily rainfall
323.4 mm at Faraway Bay on 4 Jan
(rain gauge overflowed during event)
Highest wind gust
163 km/h at Roebourne Aero on 8 Mar

Records

Record highest total annual rainfall
Total rainfall
for 2008 (mm)
Previous annual
highest
Years of
record
Annual
average
Wyndham 1624.4 1509.0 in 2006 38 805.0
Theda 1684.1 1657.3 in 1968 35 1209.6
Exmouth Town 641.3 568.4 in 1980 34 287.9
Mount Elizabeth 1359.8 1301.3 in 2007 33 960.2


Record highest annual daily rainfall
Highest daily rainfall
in 2008 (mm)
Previous annual
highest
Years of
record
Yallalong 103.0 on 21 Feb 102.0 on 10 Mar 2000 105
Albany 113.6 on 21 Nov 103.6 on 6 May 1921 104
Nalbarra 96.0 on 21 Feb 86.1 on 3 Feb 1918 95
Hamelin Station 131.0 on 30 Mar 125.0 on 9 Mar 2000 68
Muggon 152.0 on 21 Feb 142.0 on 10 Mar 2000 65
Oombulgurri 223.0 on 20 Dec 212.1 on 20 Jan 1957 58
Eneabba 78.4 on 7 Feb 75.0 on 20 Mar 1999 43
Wyndham 254.0 on 21 Dec 252.4 on 25 Mar 2006 41
Brooking Springs 207.0 on 26 Dec 190.0 on 22 Feb 1993 33

Record highest annual temperature
Highest temperature
in 2008 (°C)
Previous annual
highest
Years of
record
Annual
average
Port Hedland Airport 49.0 on 11 Jan 48.2 on 18 Feb 1998 61 33.2
Meekatharra Airport 45.7 on 5 Jan 45.5 on 4 Feb 2007 59 28.9
Onslow 49.2 on 11 Jan 48.3 on 3 Feb 1959 49 31.3
Onslow Airport 48.9 on 11 Jan 48.7 on 21 Jan 2003 45 31.9
Telfer Aero 48.1 on 10 Jan 47.5 on 21 Dec 1990 35 34.0



Record highest annual daily minimum temperature
Highest daily minimum
temperature
in 2008 (°C)
Previous annual
highest
Years of
record
Annual
average
Roebourne 32.6 on 11 Jan 32.5 on 6 Feb 1994 52 20.5




Notes

This statement has been prepared based on information available at 1 pm on Monday 5 January 2009. 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

Western Australia Climate Services Centre
Bureau of Meteorology
Phone (08) 9263 2222
Email climate.wa@bom.gov.au