Western Australia in July 2012: Record cold and dry

  • Rainfall: 3rd driest on record for WA; driest on record for southwest WA
  • Maximum temperature: Near average for WA; 7th warmest on record for southwest WA
  • Minimum temperature: Lowest on record for WA; below average for southwest WA

Rainfall

Record low rainfall was observed across a large part of southwest WA during July 2012 (see the maps below), particularly in western districts, centred on the Lower West. Many sites observed their driest July on record, including the centres of Perth, Northam, Goomalling, Narrogin, Wagin, and Collie; all of which have over 100 years of rainfall records (see the records tables below). Averaged across the Lower Southwest (southwest of a line from Jurien Bay to Bremer Bay), July 2012 was the driest July since comparable records commenced in 1900, with a total of 36 mm. The previous lowest July total rainfall for this region occurred in 1918 (47 mm), whilst the third lowest was 2005 (48 mm). The very low rainfall during July 2012 was the result of persistent high pressure systems over southern WA during the month and a contraction of the usual fronts and westerly winds southwards.

Below to very much below average rainfall was observed in much of the remainder of the Southwest Land Division (SWLD), apart from areas in the South and Southeast Coastal districts where rainfall was above to very much above average where an onshore flow for much of the month resulted in consistent showers. The SWLD recorded its second driest July, only behind the July of 2005.

Very low rainfall totals were observed across the state outside of the SLWD, however this is not uncommon for this time of year. The low rainfall throughout much of WA resulted in July 2012 ranking as the 3rd driest on record for WA behind 1937 and 1977.

Individual rainfall events over southern WA were mainly confined to cold fronts moving through the region on the 6th to 8th, 10th to 12th, 16th to 17th, and 23rd to 24th. Otherwise, strong ridging over southern WA resulted in generally clear conditions across much of the state for the month, aside from onshore showers along the south coast. A stronger cold front moved over the southwest corner early on the 31st, bringing widespread rainfall to the SWLD.

The very dry July in the Lower Southwest follows a near average June and the 7th driest autumn on record for the region. As a result, the Lower Southwest has seen its 6th driest January to July period, with the driest being 2001, the 3rd driest 2010, and the 5th driest 2006 (i.e. four of the driest such periods have occurred since 2001). The Lower Southwest has also experienced its 5th driest April to July, 4th driest May to July, and 8th driest Jun to July periods on record in 2012.

Maximum temperature

Above to very much above average maximum temperatures were observed over much of western WA, as well as in the southeast of the state during July. Most of western WA was up to 2 °C warmer than normal with patches of up to 3 °C warmer than normal in the west Gascoyne. The only area with below average mean monthly maxima was in the east Kimberley and adjacent northern Interior, where temperatures were up to 3 °C cooler than normal, while the remainder of the state was close to average.

When averaged across the state as a whole, the mean maximum temperature for WA during July 2012 was near average, whilst for the Lower Southwest (southwest of a line from Jurien Bay to Bremer Bay), daytime temperatures were very much above average and ranked as the 7th warmest July on record. This continues the very warm year to date in the Lower Southwest where alomst all months have seen above average maxima, aside from February. The mean maximum for the first seven months (January to July ) was 0.9 °C above normal and ranked as the 4th warmest January to July period since comparable temperature records commenced in 1950, largely due to a very warm autumn (5th warmest) and a very warm July (7th warmest). This "warm" run of temperatures has persisted for almost three years as the Lower West has only recorded two below average months, in terms of maximum temperature, since September 2009.

Warmer than normal daytime temperatures were observed through much of western and southern WA from the 1st to the 7th as a high moved through the Bight and directed warm northeasterly winds over the area. In contrast, the high directed cool southeasterly winds over the Kimberley resulting in relatively cool daytime temperatures during this period. A trough moved eastward through WA on the 10th and 11th, with warm conditions in the northerly flow ahead of the trough over central and eastern WA. Cooler southerly winds extended across southern WA as a ridge developed in the wake of the trough, with Norseman Aerodrome observing the coolest day in WA in July 2012 with a maximum of 10.1 °C on the 10th, and cooler than normal days extended through much of WA up to the 14th. Warm days were observed across the Pilbara and adjacent Kimberley on the 17th and 18th as a trough deepened over the Gascoyne. The warmth extended across western WA from the 19th to 22nd as the trough deepened along the west coast ahead of a cold front. Warm conditions returned to western WA on the 29th and 30th due to a high in the Bight directing northerly winds over the region.

Minimum temperature

Most of WA saw below to very much below average mean minimum temperatures during July 2012, with areas of lowest on record in the central eastern and southeastern Interior, and in central parts of the Lower West and neighbouring districts. Most of WA saw overnight temperatures at least 1 °C cooler than normal, with means up to 5 °C cooler than normal in the central eastern Interior. The only areas with close to average minima for July 2012 were parts of the south coast, far northern Gascoyne, west Pilbara, and small pockets of the Kimberley.

When averaged across the state as a whole, the July 2012 mean minimum temperature ranked as the coldest on record for WA. Comparable records commenced in 1950. The very cold July, combined with each month during 2012 recording overnight temperatures below the average (including the 4th coldest May), has resulted in WA observing its 3rd coolest January to July period on record. The Lower Southwest (southwest of a line from Jurien Bay to Bremer Bay) observed very much below average overnight temperatures during July 2012 but, in contrast to the WA average so far this year, it was only the second month to do so since October 2010.

The cool to cold overnight temperatures observed throughout much of WA during July 2012 were the result of persistent ridging across the south of the state resulting in generally clear skies and light winds, and an associated lack of rainfall, with numerous sub-zero minima observed at sites in central and southern WA throughout the month.

Further information

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Extremes in July 2012
Hottest day 35.1 °C at Wyndham Aero on the 13th
Warmest days on average 31.2 °C at Kalumburu
Coolest days on average 15.2 °C at Katanning
Coldest day 10.1 °C at Norseman Aero on the 10th
Coldest night -4.2 °C at Yeelirrie on the 7th
-4.2 °C at Warburton Airfield on the 8th
Coolest nights on average 0.8 °C at York
Warmest nights on average 21.1 °C at Troughton Island
17.9 °C at Truscott
Warmest night 23.1 °C at Troughton Island on the 28th
21.5 °C at Truscott on the 13th
Wettest overall 141.4 mm at Walpole
Wettest day 39.0 mm at Warra Jarra on the 8th
Highest wind gust 87 km/h at Geraldton Airport on the 10th

Maps
ObservedAnomalyDecile rank
Total
rainfall
Map of Rainfall totals Map of Percentage of normal rainfall Map of Rainfall deciles
Mean
daily
maximum
temperatures
Map of Mean maximum temperature Map of Anomaly in mean maximum temperature Map of Decile rank of mean maximum temperature
Mean
daily
minimum
temperatures
Map of Mean minimum temperature Map of Anomaly in mean minimum temperature Map of Decile rank of mean minimum temperature

Record lowest total July rainfall
Total rainfall
for July 2012 (mm)
Previous driest
for July
Years of
record
Average for
July
Perth Metro* 34.6 61.5 in 1876 137 165.4
Northam 13.6 19.6 in 1937 132 82.4
Bannister 31.8 36.3 in 1909 128 122.7
Jarrahdale 47.8 72.7 in 1959 128 227.1
Williams 21.0 27.4 in 1976 128 96.5
Beverley 13.4 19.7 in 1957 127 77.5
Pingelly 9.6 22.3 in 1909 122 81.6
Wagin 17.8 19.9 in 1959 122 70.9
Broomehill 14.8 20.9 in 1937 121 68.2
Narrogin 8.8 24.9 in 1957 121 87.1
Greenbushes 37.1 49.2 in 1918 120 167.4
Kellerberrin 9.7 9.9 in 2005 119 51.6
Doongin Peak 7.0 7.6 in 2005 118 53.3
Collie 42.0 51.7 in 1918 114 177.5
Darkan 19.8 34.2 in 2005 111 99.9
Mundaring 43.8 58.7 in 1889 111 214.5
Goomalling 8.2 12.2 in 1957 110 64.4
Cape Naturaliste 49.8 67.6 in 2001 108 161.2
Berkshire Valley 13.0 16.8 in 1957 106 82.5
Brookton 10.5 23.0 in 1909 104 84.7
Chidlow 21.8 55.5 in 1959 104 180.0
Quairading 12.0 12.7 in 1957 102 62.7
Tammin 5.4 10.0 in 2005 102 55.5
Rushy Pool 8.0 13.8 in 1957 101 67.6
Barberton 9.8 18.3 in 1937 100 84.1
Dalwallinu Comparison 14.7 17.4 in 1937 100 59.7
Wattening 12.2 22.7 in 1976 100 81.0
Chamingup 19.0 30.1 in 1957 98 89.6
Dellyanine 21.4 25.0 in 1957 97 77.4
Manjimup 42.0 42.7 in 1918 97 174.5
Forest Grove 88.0 90.3 in 1971 86 222.2
Ygnattering 7.0 11.0 in 1957 85 54.9
Margaret River 80.4 93.0 in 2001 84 215.7
Kondut 10.2 11.9 in 1937 81 57.7
Woodanilling 22.2 22.6 in 1957 79 72.9
Dwellingup 53.6 93.7 in 1976 77 237.0
Happy Valley 10.8 11.5 in 1937 76 58.4
Bulyee 15.0 18.8 in 1976 74 64.1
Cowaramup 91.8 94.6 in 2001 74 222.1
Waroona 47.0 76.3 in 1959 73 189.5
Roelands 59.2 65.0 in 2001 71 174.3
Perth Airport 30.6 63.4 in 2005 69 157.3
Cranham 16.2 26.6 in 2005 59 77.9
Dandaragan West 32.4 42.2 in 1976 58 118.8
Pearce RAAF 23.2 54.4 in 1976 58 135.2
Chapman Hill 53.8 58.4 in 2001 54 171.2
Swanara 10.6 12.8 in 2005 52 46.3
Gidgegannup 28.0 28.8 in 2005 51 184.3
Gosnells City 35.6 70.3 in 2005 51 162.0
Badgingarra Research Stn 24.0 25.8 in 1976 50 104.7
Albany Airport Comparison 55.0 56.6 in 1965 49 119.9
Avondale Farm 13.4 18.9 in 1976 48 70.1
Karnet 24.8 104.6 in 1998 48 218.2
Bickley 31.6 97.4 in 1976 44 217.5
Culford 19.4 50.0 in 1976 43 127.6
Kalbarri 6.8 7.0 in 1992 41 70.8
Ferguson Valley 61.0 81.2 in 2001 40 174.6
Bindoon 21.0 36.8 in 1976 39 139.3
Swan View 24.6 61.0 in 2005 39 159.8
Jandakot Aero 34.6 76.4 in 1976 38 174.5
Jarrahwood 44.4 66.0 in 2001 37 174.5
Pickering Brook 28.7 94.6 in 1976 36 198.9
Gibb Rock 10.2 15.0 in 2005 31 45.0
Medina Research Centre 39.4 76.1 in 2005 30 147.9



Record highest July temperature
Highest temperature
in July 2012 (°C)
Previous warmest
for July
Years of
record
Average for
July
Jurien Bay 26.2 on the 21st = 26.2 on the 15th in 1977 43 19.4



Record highest July mean daily maximum temperature
Mean daily maximum
temperature
for July 2012 (°C)
Previous warmest
for July
Years of
record
Average for
July
Dwellingup 16.6 16.5 in 1976 74 15.0



Record lowest July temperature
Lowest temperature
in July 2012 (°C)
Previous coolest
for July
Years of
record
Average for
July
Beverley -2.6 on the 19th = -2.6 on the 20th in 1997 43 5.2
Jurien Bay 0.5 on the 25th 0.6 on the 26th in 1990 43 9.4



Record lowest July mean daily minimum temperature
Mean daily minimum
temperature
for July 2012 (°C)
Previous coolest
for July
Years of
record
Average for
July
Northam 1.9 = 1.9 in 1997 108 5.4
Corrigin 1.9 2.0 in 1997 64 4.9
Giles Meteorological Office 3.1 3.7 in 1983 55 6.9
Karnet 4.4 4.6 in 2006 46 6.2
Brookton 2.0 2.1 in 2010 44 4.6
Ongerup 4.3 = 4.3 in 2010 44 5.8
Beverley 1.8 2.6 in 2010 42 5.2
Jurien Bay 6.1 7.0 in 2010 42 9.4
Hyden 2.3 2.6 in 2010 39 4.7
Warburton Airfield 2.0 3.0 in 1943 37 5.8



Summary statistics for July 2012
Maximum temperatures
for July
(°C)
Minimum temperatures
for July
(°C)
Rainfall
for July
(millimetres)
Mean for
July
2012
Diff
from
average
Highest for
July
2012
Mean for
July
2012
Diff
from
average
Lowest for
July
2012
Total for
July
2012
Average
for
July
Rank of
July
2012
Fraction of
July
average
North Kimberley (district 01)
Doongan 28.9 -0.8 32.0 11th 9.1 -1.7 5.1 23rd 0 0.4 v low 0%
Kalumburu 31.2 -0.8 34.2 13th 14.3 +0.5 9.0 8th 0 0.3 v low 0%
Mount Elizabeth 27.7 -0.8 31.0 11th 5.7 -2.6 -0.1 4th 0 3.1 lowest 0%
Troughton Island 27.6 -0.6 29.7 15th 21.1 -1.1 19.2 24th 0 2.8 v low 0%
Truscott 30.2   33.3 15th 17.9   14.9 8th 0
Wyndham 29.9 -1.3 34.4 13th 15.1 -1.9 10.8 22nd 0 3.1 lowest 0%
Wyndham Aero 30.4 -1.4 35.1 13th 14.2 -1.0 9.6 3rd 0 3.1 v low 0%
East Kimberley (district 02)
Argyle Aerodrome 28.3 -1.4 33.9 11th 13.6 -2.1 9.5 4th 0 1.4 v low 0%
Halls Creek Airport 25.6 -1.6 31.3 11th 11.3 -1.3 7.1 7th 0 6.0 lowest 0%
Kununurra Aero 29.8 -0.7 34.3 13th 13.4 -1.8 6.7 7th 0 1.7 lowest 0%
Warmun 28.0 -1.5 34.0 11th 12.2 -0.4 7.0 7th 0 5.4 lowest 0%
West Kimberley (district 03)
Bidyadanga 29.2 -0.3 33.6 19th 13.3 -0.7 10.2 4th 0 8.4 lowest 0%
Broome Airport 28.4 -0.4 33.1 18th 12.8 -0.9 7.5 9th 0 7.2 lowest 0%
Curtin Aero 29.9 -1.1 34.5 18th 13.3 -2.1 6.2 8th 0 7.9 v low 0%
Derby Aero 29.7 -1.0 33.2 18th 11.8 -3.1 6.1 9th 0 7.6 lowest 0%
Fitzroy Crossing Aero 29.3 -1.5 33.1 17th 9.8 -2.5 3.9 4th 0 6.7 v low 0%
West Roebuck 29.8 -1.2 34.4 18th 10.0 -2.6 4.2 3rd 0 19.6 v low 0%
De Grey (district 04)
Bedout Island 23.9   27.0 25th        
Karratha Aero 25.6 -0.7 29.8 25th 11.6 -2.2 7.3 7th 0.2 14.2 low 1%
Legendre Island 23.5   25.9 12th 16.7   13.6 7th
Mandora 28.4 -0.5 32.8 19th 10.0 -2.5 2.8 9th 0 8.8 lowest 0%
Marble Bar 26.4 -0.9 30.8 18th 10.8 -1.4 5.4 9th 0 19.3 v low 0%
Pardoo Station 27.2 -0.8 31.0 18th 11.4 -1.6 4.5 14th 0 9.7 lowest 0%
Port Hedland Airport 27.1 -0.1 30.9 25th 10.6 -1.7 5.8 9th 0 11.1 lowest 0%
Roebourne 27.1 +0.3 30.9 24th 11.9 -1.7 6.4 8th 0.2 13.7 average 1%
Roebourne Aero 26.8 -1.2 30.6 25th 9.8 -2.6 4.5 8th 0.4 10.3 average 4%
Fortescue (district 05)
Barrow Island Airport 23.0 -0.8 27.2 24th 15.8 -1.9 11.8 15th 1.0 13.7 average 7%
Learmonth Airport 25.0 +0.8 28.8 25th 10.0 -1.5 4.0 6th 0.8 22.2 low 4%
Mardie 28.0 +0.3 32.1 20th 10.6 -1.2 5.9 9th 0.2 13.3 average 2%
Onslow Airport 26.2 +0.9 30.8 25th 12.2 -0.7 7.5 16th 1.2 19.7 low 6%
Wittenoom 24.3 +0.1 28.1 17th 10.4 -1.1 4.0 15th 0 13.9 lowest 0%
West Gascoyne (district 06)
Carnarvon Airport 24.7 +2.4 28.8 21st 8.8 -2.2 3.3 6th 10.6 45.3 low 23%
Denham 22.2 +0.5 27.0 30th 13.4 +0.8 10.0 6th 30.2 40.0 average 76%
Emu Creek Station 26.6 +1.2 31.1 20th 10.3 -1.0 5.6 7th 1.6 21.8 average 7%
Murchison 21.9 +1.0 26.0 31st 4.3 -1.9 0.0 3rd 13.8 29.0 average 48%
Shark Bay Airport 22.9 +0.2 27.3 30th 9.4 -1.2 4.7 4th 28.2 30.4 average 93%
East Gascoyne (district 07)
Newman Aero 22.5 -0.5 26.8 17th 4.4 -1.8 -0.7 5th 0 14.9 lowest 0%
Paraburdoo Aero 24.8 0.0 29.8 20th 8.6 -1.2 1.8 6th 1.0 14.6 low 7%
Murchison (district 07A)
Meekatharra Airport 20.1 +1.1 24.0 10th 6.5 -0.9 1.8 13th 0.8 21.6 v low 4%
Mount Magnet Aero 19.1 +0.5 24.2 31st 5.4 -1.6 2.1 13th 10.6 32.4 low 33%
North Coast (district 08)
Carnamah 18.7 +0.8 24.5 21st 6.1 -1.2 1.7 25th 19.3 67.6 v low 29%
Dalwallinu Comparison 17.8 +0.8 23.0 22nd 5.5 -1.1 2.1 25th 14.7 59.7 lowest 25%
Geraldton Airport 20.6   24.3 30th 7.3   1.8 25th 32.2
Geraldton Airport Comparison 20.5 +1.0 24.9 21st 7.5 -1.9 1.6 25th 44.4 91.8 low 48%
Kalbarri 23.5 +1.8 27.8 20th 8.6 -1.1 1.4 6th 6.8 70.8 lowest 10%
Morawa Airport 19.1 +0.6 23.7 22nd 4.9 -1.2 1.3 25th 32.0 45.3 low 71%
Mullewa 20.3 +1.5 25.7 20th 7.0 0.0 2.4 13th 12.8 60.0 v low 21%
North Island 21.1 +0.1 25.2 21st 14.5 -0.9 7.7 16th 60.8 75.8 average 80%
Wongan Hills 18.0 +1.0 22.7 21st 5.1 -1.5 0.0 25th 14.6 69.4 v low 21%
Central Coast (district 09)
Badgingarra Research Stn 18.2 +0.6 23.4 21st 6.6 -0.7 1.8 25th 24.0 104.7 lowest 23%
Bickley 15.9 +0.9 20.2 21st 6.3 -0.8 2.9 9th 31.6 217.5 lowest 15%
Champion Lakes 18.5   22.9 21st 7.6   2.7 25th 30.2
Garden Island HSF 17.8 0.0 22.3 30th 9.9 -1.2 5.6 13th 40.6 114.4 v low 35%
Gingin Aero 18.9 +0.7 24.2 21st 3.6 -2.7 -2.7 25th 44.6 123.7 v low 36%
Gosnells City 19.5 +0.9 24.2 30th         35.6 162.0 lowest 22%
Jandakot Aero 18.9 +1.1 23.7 30th 3.8 -3.0 -1.6 25th 34.6 174.5 lowest 20%
Jurien Bay 20.6 +1.2 26.2 21st 6.1 -3.3 0.5 25th 46.9 112.7 v low 42%
Karnet 16.7 +1.3 21.8 21st 4.4 -1.8 -0.5 19th 24.8 218.2 lowest 11%
Lancelin 20.6 +1.5 25.0 30th 8.0 -2.0 3.0 9th 46.4 121.1 v low 38%
Medina Research Centre 19.4 +1.2 24.0 21st 5.4 -2.9 0.3 25th 39.4 147.9 lowest 27%
Pearce RAAF 18.8 +1.0 23.1 30th 5.6 -2.9 -0.8 25th 23.2 135.2 lowest 17%
Perth Airport 19.2 +1.3 23.8 21st 5.6 -2.4 -0.7 25th 30.6 157.3 lowest 19%
Perth Metro* 19.4 +1.1 23.8 30th 5.2 -2.5 0.4 25th 34.6 165.4 lowest 21%
Rottnest Island 18.0 +0.3 22.1 30th 12.2 -0.1 9.1 18th 54.8 143.9 v low 38%
Swanbourne 19.5 +1.2 24.4 30th 7.8 -1.9 3.9 25th 42.0 145.8 v low 29%
South Coast (district 09A)
Albany 17.2 +1.5 22.1 21st 9.2 +1.1 5.8 9th 80.6 143.6 v low 56%
Albany Airport 16.8   20.2 21st 6.7   2.7 5th 75.2
Albany Airport Comparison 16.6 +0.8 20.1 21st 6.9 -0.6 2.8 5th 55.0 119.9 lowest 46%
Bridgetown 16.1 +0.4 20.2 30th 3.4 -1.0 -2.0 9th 52.8 118.1 v low 45%
Bridgetown Comparison 17.1 +1.3 21.9 30th 3.3 -1.1 -1.5 5th 48.2 146.1 v low 33%
Bunbury 17.5 +0.3 21.6 21st 5.4 -1.7 0.1 18th 55.4 142.9 v low 39%
Busselton Aero 16.8 +0.1 21.0 21st 5.5 -1.3 1.1 9th 49.6 128.9 v low 38%
Cape Leeuwin 17.7 +1.3 21.5 5th 12.0 +0.7 7.1 9th 70.4 181.5 v low 39%
Cape Naturaliste 17.2 +0.9 21.0 5th 10.6 +0.2 5.1 24th 49.8 161.2 lowest 31%
Collie East 16.7   21.3 21st 1.9   -2.4 5th 39.2 122.2 v low 32%
Donnybrook 17.6 +1.1 22.0 30th 4.6 -1.1 0.0 9th 57.9 186.3 v low 31%
Dwellingup 16.6 +1.6 21.6 21st 3.2 -2.3 -1.1 19th 53.6 237.0 lowest 23%
Esperance 17.9 +0.8 22.1 21st 8.0 -0.3 4.7 20th 69.6 96.4 low 72%
Esperance Aero 16.5 +0.2 20.2 6th 6.8 -0.8 3.2 20th 67.0 78.9 average 85%
Harvey 17.7 +0.6 21.5 21st 6.2 -1.3 0.5 24th 40.4 149.1 v low 27%
Hopetoun North 18.1 0.0 23.5 31st 7.7 0.0 3.0 5th 129.8 69.8 v high 186%
Mandurah 17.8 +0.4 21.3 21st 9.6 -1.1 5.8 19th 55.8 117.1 low 48%
Manjimup 15.6 +1.3 20.4 30th 6.6 +0.2 1.8 9th 42.0 174.5 lowest 24%
North Walpole 16.4   20.1 21st 8.5   4.2 9th 99.8
Pemberton 16.3 +1.3 20.5 30th 7.5 +0.3 3.3 24th 86.1 209.6 v low 41%
Rocky Gully 15.3 +0.7 18.9 21st 6.3 -0.1 0.3 9th 53.4 96.0 v low 56%
Windy Harbour 17.2 +0.5 21.7 30th 9.0 +0.4 2.5 9th 115.8 190.9 low 61%
Witchcliffe 16.5 +0.1 20.4 21st 6.9 -1.1 1.3 9th 82.6 183.3 v low 45%
North Central (district 10)
Bencubbin 17.1 +0.7 22.1 21st 4.8 -1.2 0.1 19th 15.0 45.4 v low 33%
Cunderdin Airfield 18.0 +1.1 23.6 21st 1.9 -2.8 -2.9 19th 4.2 48.9 v low 9%
Kellerberrin 17.3 +0.9 22.0 21st         9.7 51.6 lowest 19%
Merredin 17.5 +1.2 22.0 6th 3.9 -1.6 -2.5 25th 15.9 50.6 v low 31%
Northam 18.0 +1.1 22.0 30th 1.9 -3.5 -2.9 25th 13.6 82.4 lowest 17%
York 17.3 +0.4 21.5 30th 0.8 -3.0 -3.1 25th 14.6 70.5 v low 21%
South Central (district 10A)
Beverley 17.7 +0.9 22.0 21st 1.8 -3.4 -2.6 19th 13.4 77.5 lowest 17%
Brookton 16.6 +0.5 20.8 21st 2.0 -2.6 -2.1 19th 10.5 84.7 lowest 12%
Corrigin 16.4 +1.1 20.5 5th 1.9 -3.0 -2.3 19th 16.4 59.4 v low 28%
Hyden 17.6 +1.2 22.0 21st 2.3 -2.4 -3.5 19th 12.9 47.7 v low 27%
Jacup 16.2 +0.6 21.1 5th 4.6 -1.0 1.1 18th 53.6 50.7 average 106%
Katanning 15.2 +0.5 19.1 21st 5.1 -0.9 1.1 18th 22.8 64.6 v low 35%
Katanning Comparison 16.0 +1.4 20.2 21st         24.1 75.2 v low 32%
Lake Grace 16.1 +0.5 20.3 6th 3.8 -1.5 -1.1 18th 18.0 38.0 v low 47%
Lake Grace Comparison 16.2 +0.8 20.4 22nd 4.0 -1.6 -0.8 18th 13.6 47.4 v low 29%
Narembeen 17.6 +1.1 21.8 21st 3.4 -2.1 -1.6 25th 13.7 49.6 v low 28%
Narrogin 16.0 +1.4 20.5 21st 2.9 -2.4 -1.2 9th 8.8 87.1 lowest 10%
Newdegate Research Station 16.2 +1.1 20.3 21st 2.6 -1.5 -2.6 20th 6.4 47.6 v low 13%
Ongerup 15.9 +1.0 20.0 5th 4.3 -1.5 -0.5 18th 38.5 49.7 average 77%
Pingelly 16.4 +1.1 20.3 21st 3.6 -2.0 -1.0 19th 9.6 81.6 lowest 12%
Ravensthorpe 16.9 +0.6 21.4 31st 6.3 -0.4 2.3 18th 73.7 47.0 high 157%
Wagin 16.1 +0.8 20.9 21st 3.2 -2.4 -1.0 9th 17.8 70.9 lowest 25%
Wandering 16.0 +0.3 19.8 21st 1.1 -2.9 -2.5 9th 19.6 94.7 v low 21%
Eucla (district 11)
Balladonia 18.1 +0.5 23.0 7th 3.2 -1.6 -0.9 19th 24.6 20.4 average 121%
Eucla 18.1 +0.1 22.7 24th 5.8 -1.2 1.4 7th 22.8 25.2 average 90%
Eyre 19.1 +1.0 23.5 31st 3.0 -2.8 -3.5 20th 41.5 34.4 average 121%
Forrest 18.9 +0.3 23.3 24th 2.5 -2.7 -1.9 1st 1.4 17.0 v low 8%
Red Rocks Point 18.6   23.9 8th 6.6   2.6 7th 13.8
South East (district 12)
Bulga Downs 19.4   23.2 31st 3.1   -1.3 7th 11.5 24.1 average 48%
Kalgoorlie-Boulder Airport 16.8 +0.1 22.4 31st 3.7 -1.3 0.1 19th 33.4 25.0 high 134%
Laverton Aero 18.2 -0.1 22.2 31st 3.9 -2.1 -1.0 14th 1.8 17.8 low 10%
Leinster Aero 18.6 -0.1 22.0 31st 4.1 -2.1 1.0 5th 1.6 19.5 low 8%
Leonora 18.0 -0.4 22.1 31st 3.7 -2.4 0.1 16th 9.9 18.9 average 52%
Leonora Aero 18.5   22.8 31st 3.4   -0.8 16th 4.6
Munglinup West 16.6 0.0 22.1 6th 6.0 -0.7 2.9 19th 81.2 42.2 v high 192%
Norseman Aero 17.3 0.0 22.7 31st 1.4 -2.9 -3.0 20th 15.8 20.0 average 79%
Salmon Gums Res.Stn. 17.0 +1.0 22.5 31st 2.9 -1.7 -2.8 21st 30.8 36.9 average 83%
Southern Cross Airfield 17.0 +0.5 21.8 31st 1.4 -2.1 -2.9 25th 13.0 34.6 v low 38%
North East (district 13)
Balgo Hills 24.1 -2.4 29.5 11th 10.6 -1.9 6.5 3rd 0 8.5 lowest 0%
Carnegie                 0 11.5 lowest 0%
Giles Meteorological Office 19.1 -0.9 24.7 11th 3.1 -3.8 0.3 3rd 0 11.7 lowest 0%
Telfer Aero 24.8 -0.5 29.2 18th 8.5 -2.2 4.4 4th 0 13.2 lowest 0%
Warburton Airfield 19.8 -0.9 25.0 24th 2.0 -3.8 -4.2 8th 0 12.9 lowest 0%
Wiluna 20.3 +0.9 25.4 10th         0.5 15.1 low 3%
Offshore Islands (district 200)
Christmas Island Aero 26.3 +0.1 26.8 6th 22.7 +0.2 21.6 26th 12.6 94.8 low 13%
Cocos Island Airport 28.7 +0.7 29.7 4th 25.0 +1.0 21.2 14th 165.4 213.6 average 77%
Varanus Island 23.3 -1.0 26.1 25th 18.9 -1.0 17.0 6th 0 10.4 v low 0%

Notes

A Monthly Climate Summary is prepared to list the main features of the weather in Western Australia 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 10 am on Wednesday 1 August 2012. 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 30 years of data.

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

Further information

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