Western Australia in July 2011: Warm nights in WA.

  • Rainfall: Above average for WA; near average in southwest WA.
  • Maximum temperature: Near average for WA.
  • Minimum temperature: Fourth warmest on record for WA; near average for southwest WA.

Rainfall

Rainfall during July 2011 was above to very much above average over parts of the Pilbara, Gascoyne, Goldfields, Interior and Eucla mainly due to a number of cloudbands crossing WA during the month. Rainfall totals in the Southwest Land Division (SWLD) were mostly close to average, although some areas received above average rainfall and some below (see July 2011 rainfall totals & deciles)

When averaged across the state, rainfall during July 2011 was above average. A number of strong cold fronts crossed the southwest of the state during the latter part of July 2011 resulting in the Lower Southwest (southwest of a line from Jurien Bay to Bremer Bay) receiving near average rainfall, and Bickley recording 270.0 mm for the month, the highest monthly total for WA. Interestingly the Lower Southwest received more rainfall in the June to July period in 2011 than was recorded during the entire winter of 2010, though despite this, January to July rainfall during 2011 was still very much below average.

Milly Milly in the Gascoyne observed its wettest July day in 101 years of record with 50.0 mm on the 10th as an intense cloudband developed over WA, while Wynyangoo (near Mount Magnet) observed its wettest July in 48 years of record as a consequence of the cloudband and other rainfall events during the month that resulted in 12 rain days at the station.

The passage of a cold front on the 22nd produced a tornado near Serpentine during the afternoon and flash flooding in Fremantle. Another frontal system on the 25th produced sustained rainfall over Cape Leeuwin which recorded 30.4 mm in 1 hour and a total of 64.8 mm in 7 hours, which is a one in 20 to 50 year event. A strong cold front moved through southwest parts of WA from late in the afternoon on the 27th bringing heavy showers, thunderstorms, severe wind gusts and a possible tornado in Waroona during the evening. A deep low then passed to the south of WA during the morning of the 28th with a secondary front moving through southern parts of WA bringing further rainfall. A deep low to the south of the state produced a strong westerly gradient over the south west of WA with embedded fronts from the 29th through to the end of the month

Maximum temperature

July 2011 maximum temperatures were above to very much above average in the western Kimberley where temperatures were up to 3 °C above normal, while the remainder of WA saw either near average or above average daytime mean temperatures (see July 2011 mean maximum temperature decile & anomaly maps)

When averaged across the state during July 2011, the mean daily maximum temperature was near average in WA.

A cooler than normal start to the month was experienced in central and southern parts of WA, culminating in very cold days on the 10th and 11th due to a cloudband over much of the state. Bulga Downs observed the coldest day in WA for July 2011 during this time, with a maximum of just 8.9 °C on both the 10th and 11th, and a number of sites in the northern Goldfields, southern Gascoyne and northern SWLD broke their lowest July daily maximum temperature records.

Minimum temperature

Apart from most of the Kimberley and Southwest districts of WA, which saw near average overnight minima, mean minimum temperatures for July were above to very much above average over almost all of WA, with an area of highest on record in the Eucla, Goldfields and southeast SWLD (see July 2011 minimum temperature decile & anomaly maps). Eucla and Hyden recorded their the warmest July on record in terms of mean daily minimum temperature in 74 and 38 years of record respectively.

When averaged across the state, July 2011 was the fourth warmest in terms of mean minimum temperature since comparable records commenced in 1950.

An unusually warm night was experienced on the last night of the month in much of the SWLD in a strong westerly pressure gradient, and Ravensthorpe observed its warmest July night in 49 years of record.

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Extremes in July 2011
Hottest day 34.8 °C at Curtin Aero on the 17th
Warmest days on average 32.0 °C at West Roebuck
Coolest days on average 14.4 °C at Katanning
Coldest day 8.9 °C at Bulga Downs on the 10th
8.9 °C at Bulga Downs on the 11th
Coldest night -3.0 °C at Yeelirrie on the 6th
Coolest nights on average 4.6 °C at Bridgetown Comparison
4.6 °C at Collie East
Warmest nights on average 22.3 °C at Troughton Island
18.5 °C at Truscott
Warmest night 24.0 °C at Troughton Island on the 12th
22.1 °C at Truscott on the 12th
Wettest overall 270.0 mm at Bickley
Wettest day 66.8 mm at Rottnest Island on the 21st
Highest wind gust 130 km/h at Cape Leeuwin on the 28th

Record highest July daily rainfall
Highest daily rainfall
in July 2011 (mm)
Previous wettest
for July
Years of
record
Milly Milly 50.0 on the 10th 42.7 on the 19th in 1980 101



Record highest total July rainfall
Total rainfall
for July 2011 (mm)
Previous wettest
for July
Years of
record
Average for
July
Wynyangoo 117.0 108.5 in 1996 48 31.9



Record lowest July daily maximum temperature
Lowest daily maximum
temperature
in July 2011 (°C)
Previous coolest
for July
Years of
record
Average for
July
Leonora 10.0 on the 11th 10.6 on the 14th in 2004 55 18.5
Badgingarra Research Stn 10.4 on the 10th 11.4 on the 9th in 2010 45 17.6
Lancelin 12.8 on the 10th 13.3 on the 15th in 1986 44 19.1
Jurien Bay 13.0 on the 10th 14.0 on the 19th in 1991 42 19.4
Hyden 9.5 on the 11th 9.6 on the 1st in 1998 39 16.3



Record highest July daily minimum temperature
Highest daily minimum
temperature
in July 2011 (°C)
Previous warmest
for July
Years of
record
Average for
July
Ravensthorpe 13.7 on the 31st 13.6 on the 30th in 2001 49 6.7



Record highest July mean daily minimum temperature
Mean daily minimum
temperature
for July 2011 (°C)
Previous warmest
for July
Years of
record
Average for
July
Eucla 8.8 8.6 in 1926 74 7.0
Hyden 7.2 6.5 in 2007 38 4.6


Summary statistics for July 2011
Maximum temperatures
for July
(°C)
Minimum temperatures
for July
(°C)
Rainfall
for July
(millimetres)
Mean for
July
2011
Diff
from
average
Highest for
July
2011
Mean for
July
2011
Diff
from
average
Lowest for
July
2011
Total for
July
2011
Average
for
July
Rank of
July
2011
Fraction of
July
average
North Kimberley (district 01)
Doongan 29.0 -0.8 31.0 14th 11.1 +0.3 6.1 24th 0 0.4 v low 0%
Kalumburu 31.6 -0.4 33.4 31st 13.5 -0.3 8.2 26th 0 0.3 v low 0%
Kuri Bay 31.7 +0.6 33.0 17th     16.2 24th 0 4.7 lowest 0%
Mount Elizabeth 28.2 -0.3 30.0 17th 10.2 +2.1 4.2 25th 9.0 3.4 high 265%
Troughton Island 27.8 -0.4 28.8 30th 22.3 +0.2 20.8 26th 0.4 2.9 high 14%
Truscott 30.5   32.6 31st 18.5   15.8 26th 0
Wyndham 30.9 -0.3 32.9 14th 16.6 -0.4 11.6 26th 0 3.2 lowest 0%
Wyndham Aero 31.5 -0.3 33.5 14th 15.9 +0.7 10.1 25th 0 3.2 v low 0%
East Kimberley (district 02)
Argyle Aerodrome 29.3 -0.4 31.8 3rd 15.9 +0.2 11.7 10th 0 1.4 v low 0%
Halls Creek Airport 27.2 0.0 30.4 3rd 13.5 +0.9 7.7 23rd 0 6.1 lowest 0%
Kununurra Aero 30.3 -0.2 32.1 17th 14.8 -0.4 8.9 25th 0 1.7 lowest 0%
Warmun 29.4 -0.1 31.7 31st 13.4 +0.8 7.1 26th 0 5.5 lowest 0%
West Kimberley (district 03)
Bidyadanga 31.3 +1.9 33.5 8th 15.4 +1.5 11.0 31st 2.0 8.4 average 24%
Broome Airport 30.5 +1.7 33.2 27th 14.9 +1.3 10.9 31st 0 7.3 lowest 0%
Curtin Aero 31.7 +0.8 34.8 17th 16.0 +0.6 9.4 26th 0 8.3 v low 0%
Cygnet Bay 28.2 0.0 31.9 16th 14.4 -0.4 10.0 25th 0 6.4 lowest 0%
Derby Aero 31.1 +0.5 32.9 17th 15.1 +0.2 9.2 23rd 0 7.8 lowest 0%
Fitzroy Crossing Aero 30.8 0.0 32.9 16th 13.3 +1.1 7.8 23rd 0 7.1 v low 0%
West Roebuck 32.0 +1.1 34.5 17th 14.2 +1.7 9.8 27th 0 21.3 v low 0%
De Grey (district 04)
Bedout Island 25.1   27.0 27th 19.6   16.0 12th
Karratha Aero 26.6 +0.4 30.9 20th 14.7 +1.0 11.4 27th 8.4 14.6 average 58%
Legendre Island 24.8   29.4 20th 18.1   15.6 6th
Mandora 29.7 +0.8 33.0 19th 13.7 +1.2 7.0 28th 5.5 8.9 high 62%
Marble Bar 27.9 +0.7 32.2 27th 13.1 +1.0 10.4 28th 2.6 21.0 average 12%
Pardoo Station 28.3 +0.4 31.4 18th 13.7 +0.7 10.0 12th 24.6 9.9 high 248%
Port Hedland Airport 28.0 +0.9 31.5 20th 14.0 +1.7 10.2 27th 24.4 11.3 high 216%
Roebourne 28.4 +1.7 32.7 20th 14.6 +1.0 10.9 28th 7.0 13.8 average 51%
Roebourne Aero 28.0 0.0 31.7 20th 13.4 +1.1 9.2 27th 5.0 16.3 average 31%
Fortescue (district 05)
Barrow Island Airport 23.5 -0.3 25.7 28th 17.6 -0.1 15.2 8th 32.4 14.6 high 222%
Learmonth Airport 24.3 +0.1 28.7 28th 12.9 +1.5 8.2 7th 40.2 23.0 high 175%
Mardie 27.3 -0.4 30.5 27th 13.4 +1.7 8.5 3rd 24.0 13.4 high 179%
Onslow 25.4 +0.6 29.0 22nd 15.6 +3.9 11.9 6th 26.0 18.5 high 141%
Onslow Airport 25.4 +0.1 28.6 16th 15.0 +2.1 11.3 6th 46.4 20.1 high 231%
Wittenoom 25.1 +0.9 29.7 27th 12.7 +1.2 8.3 6th 6.9 14.1 average 49%
West Gascoyne (district 06)
Carnarvon Airport 22.9 +0.6 27.3 25th 11.7 +0.8 6.7 8th 59.0 45.8 high 129%
Denham 20.8 -0.9 24.0 15th 14.2 +1.7 9.3 7th 46.8 40.1 high 117%
Emu Creek Station 25.8 +0.4 29.7 25th 12.9 +1.7 9.1 3rd 13.2 22.1 average 60%
Gascoyne Junction 23.0 0.0 27.0 27th 11.1 +1.8 7.4 6th 22.8 27.4 average 83%
Murchison         8.5 +2.4 1.5 8th        
Shark Bay Airport 22.0 -0.7 26.7 24th 11.7 +1.2 7.3 7th 47.2 30.5 high 155%
East Gascoyne (district 07)
Newman Aero 23.0 0.0 28.4 27th 9.4 +3.4 5.6 4th 32.2 15.3 high 210%
Paraburdoo Aero 24.9 +0.1 30.6 27th 11.2 +1.5 5.9 3rd 18.0 15.0 high 120%
Murchison (district 07A)
Meekatharra Airport 19.6 +0.6 26.6 27th 8.6 +1.2 2.7 3rd 36.2 22.0 high 165%
Mount Magnet Aero 17.9 -0.8 25.0 27th 8.7 +1.8 1.7 6th 81.8 33.7 high 243%
North Coast (district 08)
Dalwallinu 16.3 -0.6 21.1 27th 7.5 +1.7 2.6 5th 63.4 48.2 average 132%
Dalwallinu Comparison 16.7 -0.3 21.5 27th 7.7 +1.1 3.5 4th 71.8 60.1 high 119%
Geraldton Airport 19.3 -0.2     9.8 +0.4            
Kalbarri 22.0 +0.3 26.1 14th 11.0 +1.3 5.2 7th 81.8 72.4 average 113%
Morawa Airport 18.0 -0.6 22.6 27th 7.5 +1.5 1.3 6th 63.4 46.1 high 138%
Mullewa 19.1 +0.4 24.0 27th 8.6 +1.7 3.4 7th 59.9 60.4 average 99%
North Island 21.1 +0.1 24.5 24th 15.4 0.0 11.3 13th 108.8 77.3 high 141%
Wongan Hills 16.8 -0.2 21.3 27th 7.7 +1.1 2.5 4th 90.6 69.9 high 130%
Central Coast (district 09)
Badgingarra Research Stn 16.8 -0.8 20.8 14th 8.4 +1.2 3.6 6th 105.0 106.3 average 99%
Bickley 15.0 0.0 18.7 14th 7.8 +0.7 3.9 4th 270.0 221.8 high 122%
Champion Lakes 17.5   21.1 14th 9.8   3.8 4th 143.6
Garden Island HSF 17.5   20.4 24th 11.5   7.4 4th 175.6 121.8 high 144%
Gingin Aero 17.8 -0.5 21.7 14th 7.6 +1.4 0.0 4th 141.6 128.6 average 110%
Gooseberry Hill 16.5 +0.1 20.3 14th 9.5 +0.4 5.1 7th
Gosnells City 18.8 +0.2 22.8 14th         137.0 164.5 low 83%
Jandakot Aero 18.2 +0.4 22.3 24th 7.5 +0.7 -0.4 4th 181.0 178.3 average 102%
Jurien Bay 19.6 +0.2 22.4 24th        
Karnet 15.6 +0.2 19.9 14th 7.3 +1.1 1.2 4th 219.8 222.4 average 99%
Lancelin 19.4 +0.3 23.5 14th 9.4 -0.6 4.5 5th 127.0 123.0 average 103%
Medina Research Centre 18.0 -0.2 22.5 24th 8.9 +0.6 1.3 4th 131.6      
Pearce RAAF 17.6 -0.2 21.9 24th 8.7 +0.2 0.7 4th 120.4      
Perth Airport 18.4 +0.5 22.1 14th 8.6 +0.6 0.2 4th 160.2 159.1 average 101%
Perth Metro* 18.3 0.0 22.0 14th 8.5 +0.7 1.3 4th 161.0 169.7 average 95%
Rottnest Island 17.3 -0.4 21.2 24th 12.3 0.0 9.2 3rd 181.6 143.9 high 126%
Swanbourne 18.2 -0.1 21.8 14th 9.9 +0.3 4.7 4th 155.2 151.5 average 102%
South Coast (district 09A)
Albany 16.7 +1.0 20.5 27th 7.9 -0.2 1.8 18th 145.7 144.0 average 101%
Albany Airport 16.0 +0.2 19.4 27th 7.2 -0.3 0.4 18th 141.6 121.1 high 117%
Bridgetown 15.5 -0.2 18.8 14th 4.7 +0.4 -2.0 18th
Bridgetown Comparison 16.5 +0.7 20.4 14th 4.6 +0.2 -1.2 18th 157.8 146.9 average 107%
Bunbury 17.2 0.0 19.9 24th 7.2 +0.1 1.5 18th 121.8 148.4 low 82%
Busselton 16.9 -0.2 19.4 15th 8.2 +0.2 2.8 4th 150.4 140.8 average 107%
Busselton Aero 16.8 +0.1 19.9 30th 6.8 0.0 1.7 17th 85.2 134.5 low 63%
Cape Leeuwin 16.9 +0.5 20.3 14th 11.3 0.0 8.0 9th 188.0 182.4 average 103%
Cape Naturaliste 16.7 +0.4 19.2 24th 10.5 +0.1 6.4 9th 111.8 162.2 low 69%
Collie East 16.0   19.5 14th 4.6   -1.9 18th 138.6
Donnybrook 17.0 +0.5 21.3 14th 6.3 +0.6 0.6 5th 176.0 187.4 average 94%
Esperance 18.1 +1.0 23.1 25th 9.1 +0.8 5.1 10th 116.0 97.1 high 119%
Esperance Aero 17.0 +0.7 21.6 31st 8.4 +0.9 4.2 17th 70.4 79.2 average 89%
Harvey 17.0 -0.2 20.2 14th 7.2 -0.3 2.8 4th 175.9 159.4 average 110%
Hopetoun North 17.8 -0.4 22.8 27th 9.0 +1.4 5.0 18th 73.0 65.8 average 111%
Jarrahwood 16.6 +0.3 20.1 14th 4.6 -0.3 -2.6 18th 168.4 178.1 average 95%
Mandurah 17.3   21.2 24th 11.0   6.3 4th 126.4 123.2 average 103%
Manjimup 15.0 +0.7 19.2 14th 6.3 -0.1 2.7 9th 204.0 175.9 high 116%
North Walpole 15.9   19.9 14th 8.7   3.5 18th  
Pemberton 15.7 +0.7 19.9 14th 7.4 +0.2 2.4 18th
Rocky Gully 14.7 +0.1 17.7 27th 6.4 0.0 1.5 18th 139.6 98.6 high 142%
Shannon 14.6 -0.3 18.2 24th 6.2 -0.2 0.6 18th 192.0 165.8 average 116%
Windy Harbour 16.9 +0.2 21.2 14th 8.4 -0.2 2.6 18th 225.5 192.6 high 117%
Witchcliffe 16.3 -0.1 18.9 27th 7.3 -0.8 1.2 18th 241.0 191.1 high 126%
North Central (district 10)
Bencubbin 16.2 -0.2 22.1 27th 7.8 +1.8 2.1 4th 73.0 45.8 high 159%
Cunderdin Airfield 16.7 -0.2 20.9 27th 7.1 +2.6 0.4 4th 62.4 51.9 average 120%
Merredin                 45.2 51.0 average 89%
Northam 17.1 +0.2 20.8 27th 6.8 +1.4 0.3 4th 93.9 82.9 average 113%
York 16.7 -0.2 20.5 27th 6.5 +2.9 0.5 4th 107.7 73.6 high 146%
South Central (district 10A)
Beverley 16.8 0.0 20.2 24th 6.7 +1.6 0.2 4th 96.8 78.0 high 124%
Brookton 15.9 -0.2 19.6 24th 6.0 +1.5 0.5 4th 88.3 85.4 average 103%
Corrigin 15.5 +0.2 19.4 27th 6.5 +1.6 0.7 5th 84.4 59.9 high 141%
Hyden 17.0 +0.7 22.5 27th 7.2 +2.6 2.0 17th 74.7 48.1 high 155%
Jacup 15.6 0.0 20.0 27th 6.5 +1.0 2.0 7th 51.4 50.6 average 102%
Katanning 14.4 -0.3 17.9 24th 6.6 +0.7 2.2 17th 61.4 68.1 average 90%
Katanning Comparison 15.0 +0.4 18.5 27th 5.6 +0.2 -1.5 18th 68.4 75.6 average 90%
Lake Grace 15.2 -0.4 19.3 24th 7.3 +2.1 2.2 17th 66.4 39.3 high 169%
Lake Grace Comparison 15.3 -0.1 19.3 24th 7.3 +1.7 2.1 17th 66.2 47.7 high 139%
Narembeen 16.5 0.0 21.3 24th 7.1 +1.7 0.9 4th 67.3 50.1 high 134%
Narrogin 14.7 +0.1 18.6 24th 5.8 +0.6 -0.3 18th 83.8 87.7 average 96%
Newdegate Research Station 15.0 -0.1 19.2 24th 6.1 +2.1 0.4 10th 72.2 48.4 high 149%
Ongerup 15.0 +0.1 19.1 27th 6.1 +0.3 1.4 17th 38.8 49.7 average 78%
Pingelly 15.4 +0.1 18.7 27th 6.5 +0.9 0.8 4th 94.6 82.2 average 115%
Ravensthorpe 16.8 +0.5 21.1 27th         48.0 46.8 average 103%
Wagin 15.3 0.0 19.3 24th 6.0 +0.4 0.5 18th 67.1 71.3 average 94%
Wandering 15.3 -0.5 19.2 27th 5.6 +1.7 -1.0 4th 133.4 100.5 high 133%
Eucla (district 11)
Balgair 18.1 -0.5 25.6 27th     0.5 5th 30.2 18.2 high 166%
Balladonia 18.1 +0.5 25.8 27th 7.0 +2.2 1.0 17th 36.0 20.4 high 176%
Eucla 18.9 +0.9 27.7 28th 8.8 +1.8 3.8 2nd 37.2 25.2 high 148%
Eyre 18.9 +0.8 28.2 27th 7.5 +1.7 1.5 11th 29.6 34.3 average 86%
Forrest 18.2 -0.4 26.6 28th 7.2 +2.1 2.2 4th 50.6 19.8 high 256%
Red Rocks Point 18.2   28.0 27th 8.9   3.4 2nd 29.6
South East (district 12)
Bulga Downs 18.6   29.0 26th 7.0   1.6 10th 68.2 24.2 v high 282%
Kalgoorlie-Boulder Airport 16.7 0.0 24.1 26th 7.4 +2.4 0.4 6th 39.8 25.0 high 159%
Laverton Aero 18.1 -0.2 26.5 27th 8.0 +2.1 0.0 4th 46.2 18.7 high 247%
Leinster Aero 18.8 +0.1 26.8 27th 8.3 +2.2 -0.3 6th 37.4 20.6 high 182%
Leonora 18.0 -0.5 26.3 26th 8.4 +2.3 2.2 9th 34.8 19.0 high 183%
Leonora Aero 18.1   26.1 26th 8.6   1.7 4th 30.4
Munglinup West 16.8   22.6 27th 7.6   3.3 10th 45.0 38.3 average 117%
Norseman Aero 17.4 +0.1 24.7 27th 6.4 +2.3 -0.4 17th 15.2 20.4 average 75%
Salmon Gums Res.Stn. 16.9 +0.9 23.2 27th 6.1 +1.5 -1.7 10th 38.0 37.0 average 103%
Southern Cross Airfield 16.5 0.0 23.4 27th 6.9 +3.7 -0.6 4th 40.0 36.0 high 111%
Yeelirrie 19.9 +0.7 27.5 27th 6.3 +2.8 -3.0 6th 37.6 17.6 high 214%
North East (district 13)
Carnegie 22.0 +0.7 28.4 28th 8.4 +2.6 2.4 8th 8.7 11.7 high 74%
Giles Meteorological Office 20.4 +0.4 27.6 31st 8.7 +1.8 1.8 7th 19.4 11.9 high 163%
Telfer Aero 25.8 +0.5 30.1 31st 12.8 +2.2 8.1 4th 13.8 13.5 high 102%
Warburton Airfield 21.2 +0.5 28.4 28th 8.2 +2.5 1.3 4th 17.4 13.2 high 132%
Wiluna 20.8 +1.4 28.0 27th 7.8 +2.4 1.5 7th 23.9 15.2 high 157%
Offshore Islands (district 200)
Christmas Island Aero 25.9 -0.4 26.8 10th 22.1 -0.4 19.0 11th 10.0 96.9 v low 10%
Cocos Island Airport 28.2 +0.2 29.2 1st 24.0 0.0 21.6 23rd 169.4 214.1 average 79%
Varanus Island 23.7 -0.7 26.0 28th 19.4 -0.5 15.3 5th 51.0 11.2 high 455%

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 Monday 1 August 2011. 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

Media
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