Western Australia in September 2011: Cool nights in the north

  • Rainfall: Near average.
  • Maximum temperature: Near average.
  • Minimum temperature: Below average for WA; near average for southwest WA.

Rainfall

September 2011 rainfall was mixed across WA. Rainfall in the Southwest Land Division (SWLD) was mostly near average, with patches of above average rainfall in central and northern parts contrasting with patches of below average rainfall in the southeast of the division. Parts of the eastern Gascoyne, western Goldfields and western Kimberley saw above average September rainfall, while areas of below average rainfall was observed in the west Gascoyne, west Pilbara, northeastern Goldfields, Interior, Eucla, and north and east Kimberley (see September 2011 rainfall totals & deciles). It should be noted that rainfall in the north of WA is typically low during September. When averaged across the state, September 2011 rainfall was close to average.

A westerly flow with embedded cold fronts over the south of the state early in the month brought moderate rainfall, whilst on the 2nd heavy falls were observed in the Lower West. Isolated lighter falls continued in the south in subsequent days before a lengthy break occurred over much of WA as a strong slow moving high dominated the weather from the 6th, with only isolated showers along the south coast on the 6th and 7th, contracting to the Eucla on the 8th and 9th and clearing the state on the 10th. A weak front brushed the southwest corner on the 12th and 13th bringing a few showers but the remainder of the state remained clear. Stronger cold fronts crossed the southwest of WA in the second half of September, culminating in wintery conditions on the 18th as a strong front moved through and brought a record daily fall for September to Frankland in the Great Southern. A westerly flow maintained showers in the far southwest over subsequent days as a ridge developed over central WA keeping the remainder of the state mostly clear. Another front crossed the south on the 21st to 22nd resulting in moderate falls in the Southwest and Lower West. Further fronts and an unstable air-mass continued the rainfall over the SWLD on the 25th to 27th, mostly clearing on the 28th.

Maximum temperature

September 2011 maximum temperatures were near average across most of WA. Areas of above to very much above average daytime temperatures were observed in the southeast of the state, with an area of up to 4 °C above normal in the western Eucla. Areas of above average temperature were also observed in the west Kimberley, west Pilbara, west Gascoyne, and most of the Southwest district. An area of below average maxima was experienced in the east Kimberley, where daytime temperatures were up to 2 °C below normal (see September 2011 mean maximum temperature deciles & anomaly maps).

When averaged across the state, the maximum temperature during September 2011 was near average. The Lower Southwest (southwest of a line from Jurien Bay to Bremer Bay) also experienced near average daytime temperatures during September 2011, however, mean maxima for the Lower Southwest in each month of 2011 have been above the long-term average (comparable records commenced in 1950). As a result the mean maximum temperature for the Lower Southwest for the 2011 January to September period is the highest on record.

Cooler than normal days were observed across the Kimberley due to a strong high to the south from the 9th to 14th, with daily maximum temperatures in the high 20s to low 30s. Warm spring days were experienced over the south of WA on the 11th and 12th, as a high to the east directed warm northerly winds ahead of a cold front. Unusually warm conditions were observed in the Eucla on the 18th, with several sites reaching the mid-30s in northerly winds ahead of a trough.

Minimum temperature

September 2011 mean minimum temperatures were below to very much below average over the Kimberley, central Pilbara, northern and eastern SWLD, as well as in much of the Goldfields and Interior. An area of lowest on record was observed in the east Kimberley where Wyndham observed its coolest September in terms of overnight temperatures, while Halls Creek Airport, Warmun and Port Hedland Airport observed their coolest September in over 30 years. Much of the remainder of the state observed near average minima, apart from parts of the Eucla and in coastal areas of the southern and western SWLD, which saw above average overnight temperatures (see September 2011 minimum temperature deciles & anomaly maps).

When averaged across the state September 2011 was below average. The Lower Southwest saw near to, but slightly above, average overnight temperatures during the month, and as with maximum temperatures, 2011 is highest on record for the January to September period. Comparable records commenced in 1950.

A warm night at Eucla ahead of a trough on the 2nd resulted in its warmest September night on record. A strong high pressure system over the south of WA resulted in cool to cold overnight temperatures at a number of locations in southern WA from the 8th to 15th. The cool air pushed northwards into the Kimberley and Pilbara, with particularly cool nights observed from the 11th to 15th. Wyndham town broke their coolest September night on record twice, on the 12th (13.5 °C) and 13th (13.8 °C), in its 43 years of record. Wyndham Aerodrome experienced its coldest night on record on the 12th (10.9 °C), followed by the second and third coldest nights on the 13th (11.2 °C) and 14th (11.8°C) in 12 years of record. Doongan also registered its lowest September temperature in 23 years of record with a chilly 5.8 °C on the 13th.

Other Phenomena

A strong cold front moved across the south of WA on the 18th causing severe wind gusts in parts of the SWLD, Goldfields and Eucla districts. Mainly minor damage was reported in Mandurah and Perth's southern suburbs, however trees reportedly fell on houses in Maddington and Westfield. Damage to property was also reported in Kalgoorlie due to severe winds, with poor visibility in raised dust and sand observed immediately ahead of the front at approximately 1330 WST. A temperature drop of about 15 degrees was observed at Kalgoorlie as the rain began to fall, although only a total of 2.8 mm was recorded.

Further information

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Extremes in September 2011
Hottest day 39.4 °C at Wyndham on the 19th
39.4 °C at Fitzroy Crossing Aero on the 24th
Warmest days on average 36.2 °C at Wyndham Aero
Coolest days on average 16.9 °C at Rocky Gully
16.9 °C at Shannon
Coldest day 11.1 °C at Narrogin on the 27th
Coldest night -4.1 °C at Eyre on the 24th
Coolest nights on average 3.9 °C at York
Warmest nights on average 24.4 °C at Cocos Island Airport
21.2 °C at Truscott
Warmest night 25.6 °C at Troughton Island on the 24th
24.4 °C at Argyle Aero on the 28th
Wettest overall 206.6 mm at Karnet
Wettest day 52.0 mm at Karnet on the 2nd
Highest wind gust 104 km/h at Forrest on the 18th

Record highest September daily rainfall
Highest daily rainfall
in September 2011 (mm)
Previous wettest
for September
Years of
record
Frankland 25.0 on the 18th 22.9 on the 14th in 1965 35



Record highest September daily minimum temperature
Highest daily minimum
temperature
in September 2011 (°C)
Previous warmest
for September
Years of
record
Average for
September
Eucla 22.1 on the 2nd 21.6 on the 29th in 1973 49 9.1



Record lowest September temperature
Lowest temperature
in September 2011 (°C)
Previous coolest
for September
Years of
record
Average for
September
Wyndham 13.5 on the 13th 14.0 on the 5th in 2003 43 22.9



Record lowest September mean daily minimum temperature
Mean daily minimum
temperature
for September 2011 (°C)
Previous coolest
for September
Years of
record
Average for
September
Wyndham 19.3 20.5 in 1976 42 22.9

Lowest September mean daily minimum temperature for at least 30 years
Mean daily minimum
temperature
for September 2011 (°C)
Most recent September
at least this cool
Years since
cooler
Average for
September
Halls Creek Airport 16.7 16.1 in 1978 33 19.0
Port Hedland Airport 14.2 13.1 in 1978 33 15.4
Warmun 16.7 16.3 in 1978 33 19.5



Summary statistics for September 2011
Maximum temperatures
for September
(°C)
Minimum temperatures
for September
(°C)
Rainfall
for September
(millimetres)
Mean for
September
2011
Diff
from
average
Highest for
September
2011
Mean for
September
2011
Diff
from
average
Lowest for
September
2011
Total for
September
2011
Average
for
September
Rank of
September
2011
Fraction of
September
average
North Kimberley (district 01)
Doongan 33.7 -1.7 36.8 26th 14.6 -3.3 5.8 13th 0 5.6 v low 0%
Kalumburu 33.9 -1.9 37.6 19th 16.3 -3.2 9.1 13th 0 1.9 v low 0%
Mount Elizabeth 32.7 -1.4 36.6 29th 11.8 -3.4 4.7 14th 0 8.9 lowest 0%
Troughton Island 29.5 -0.8 30.2 20th 23.6 -1.0 20.7 14th 1.0 0.2 v high 500%
Truscott 32.6   36.1 20th 21.2   15.8 14th 0.4
Wyndham 35.4 -1.3 39.4 19th 19.3 -3.6 13.5 13th 0 4.1 lowest 0%
Wyndham Aero 36.2 -1.5 39.3 19th 18.5 -3.7 10.9 12th 0 4.2 v low 0%
East Kimberley (district 02)
Argyle Aerodrome 34.7 -1.8 38.6 27th 19.7 -2.7 12.9 12th 0.4 2.7 average 15%
Halls Creek Airport 33.0 -1.0 37.7 27th 16.7 -2.3 10.9 12th 0 4.7 lowest 0%
Kununurra Aero 34.8 -1.8 38.4 19th 16.4 -4.0 9.3 14th 0.2 3.2 average 6%
Warmun 34.8 -1.3 38.9 27th 16.7 -2.8 10.3 1st 0 4.6 lowest 0%
West Kimberley (district 03)
Bidyadanga 33.8 +1.0 37.5 6th 16.5 -1.0 11.2 16th 0 1.3 lowest 0%
Broome Airport 32.3 +0.5 37.6 29th 17.0 -1.5 10.5 14th 1.2 1.4 average 86%
Curtin Aero 35.5 -1.0 39.1 21st 16.2 -2.4 10.6 15th 0 0.2 v low 0%
Derby Aero 34.7 -0.5 38.7 21st 16.6 -3.1 10.1 14th 0 1.1 lowest 0%
Fitzroy Crossing Aero 35.7 -1.6 39.4 24th 15.5 -3.4 9.2 12th 0.4 0.4 high 100%
West Roebuck 34.5 +0.2 39.1 29th 15.5 -2.2 8.5 12th 0.8 0.6 high 133%
De Grey (district 04)
Bedout Island 28.0   31.0 22nd 21.4   19.0 13th
Karratha Aero 30.4 -0.2 34.2 23rd 15.8 -1.2 11.8 13th 0 1.5 lowest 0%
Legendre Island 27.6   30.7 21st 19.6   15.7 13th
Mandora 33.3 -0.3 37.3 21st 15.0 -0.7 12.5 18th 0 1.0 lowest 0%
Marble Bar 33.7 -0.7 37.7 25th 16.0 -0.7 11.0 14th 0 6.1 v low 0%
Pardoo Station 32.8 0.0 36.3 25th 14.2 -1.9 9.0 17th 0 2.9 lowest 0%
Port Hedland Airport 32.2 -0.1 35.9 22nd 14.2 -1.2 9.7 15th 0.2 1.3 average 15%
Roebourne 32.6 0.0 35.7 23rd 15.7 -1.1 10.6 13th 0 1.4 lowest 0%
Roebourne Aero 32.6 -0.2 36.2 23rd 14.2 -1.4 8.7 13th 0 3.4 v low 0%
Fortescue (district 05)
Barrow Island Airport 26.7 0.0 31.4 5th 18.7 -0.7 16.0 13th 0.6 0.9 high 67%
Learmonth Airport 30.0 +0.8 34.8 24th 12.7 -1.1 8.6 13th 0 2.1 lowest 0%
Mardie 31.4 -0.8 35.0 6th 13.4 -0.9 9.7 13th 0 1.4 lowest 0%
Onslow 29.4 +0.3 34.1 15th 15.3 +1.1 12.0 4th 0 1.3 lowest 0%
Onslow Airport 30.3 +0.3 34.4 15th 15.0 -0.3 12.3 4th 0.2 1.5 average 13%
Wittenoom 31.4 +0.3 35.3 24th 15.6 -1.2 10.7 13th 0 3.3 lowest 0%
West Gascoyne (district 06)
Carnarvon Airport 25.6 +1.3 31.8 12th 12.5 -1.3 8.8 13th 3.4 5.7 average 60%
Denham 24.3 +0.6 29.0 11th 15.2 +0.5 12.3 8th 2.0 7.8 low 26%
Emu Creek Station 30.7 +0.1 34.7 24th 13.0 -1.0 9.6 13th 0 2.0 lowest 0%
Gascoyne Junction 28.5 +0.2 33.2 24th 11.8 -0.2 9.0 3rd 1.3 3.1 average 42%
Murchison 25.9 -0.1 31.0 30th         2.6 7.7 low 34%
Shark Bay Airport 26.1 +0.4 31.6 12th 12.0 -0.5 7.6 29th 2.8 7.3 v low 38%
East Gascoyne (district 07)
Newman Aero 29.7 -0.5 35.6 25th 11.6 -0.2 6.0 13th 0.2 4.5 average 4%
Paraburdoo Aero 30.8 -0.4 35.9 24th 13.0 -0.4 7.7 12th 0 3.6 lowest 0%
Murchison (district 07A)
Meekatharra Airport 25.6 0.0 31.7 24th 10.1 -1.4 5.9 3rd 1.8 4.8 average 38%
Mount Magnet Aero 23.8 -0.5 30.6 14th 9.0 -1.2 5.5 28th 14.4 9.3 high 155%
North Coast (district 08)
Carnamah 22.3 +0.3 28.2 30th 7.7 -0.4 3.5 28th 27.7 28.1 average 99%
Dalwallinu 20.5 -0.3 26.8 30th 5.9 -0.8 1.9 28th 30.4 26.2 average 116%
Dalwallinu Comparison 20.9 -0.2 27.0 30th 7.3 -0.5 3.9 28th 31.5 25.4 high 124%
Eneabba                 56.5 45.0 high 126%
Geraldton Airport 22.4   29.0 30th 8.3   3.1 29th 41.8
Geraldton Airport Comparison 22.3 +0.3 29.1 30th 8.2 -1.0 3.6 24th 22.0 31.9 average 69%
Kalbarri 24.5 +0.6 29.3 11th 9.9 -0.8 6.6 13th 14.2 23.6 low 60%
Morawa Airport 22.7 -0.1 30.4 30th 6.6 -0.8 3.1 29th 25.4 25.0 average 102%
Mullewa 23.2 -0.2 29.2 30th 8.1 -0.4 5.9 28th 18.8 21.7 average 87%
North Island 22.1 +0.2 24.9 12th 15.5 -0.3 10.9 17th 47.2 22.5 v high 210%
Wongan Hills 20.6 0.0 26.5 12th 6.9 -0.7 2.5 28th 37.0 29.2 average 127%
Central Coast (district 09)
Badgingarra Research Stn 19.7 -0.9 25.4 12th 7.5 0.0 3.0 28th 61.4 51.0 average 120%
Bickley 17.3 -0.1 23.5 12th 8.6 +0.5 4.7 28th 168.4 121.6 high 138%
Champion Lakes 19.5   23.7 12th 10.3   4.3 28th
Garden Island HSF 19.0   22.3 30th 12.0   7.8 28th 72.8 59.8 average 122%
Gingin Aero 20.4 0.0 27.2 12th 7.8 +0.5 3.8 24th 96.0 84.5 average 114%
Gosnells City 21.2 +0.6 26.0 12th         114.9 81.2 high 142%
Jandakot Aero 20.0 +0.1 24.2 12th 8.1 0.0 3.4 29th 114.4 85.4 high 134%
Jurien Bay 22.0 +0.8 26.0 30th 11.1 +1.2 7.0 8th 52.5 44.4 average 118%
Karnet 17.7 +0.2 23.0 11th 7.4 +0.2 2.1 28th 206.6 129.8 v high 159%
Lancelin 21.3 +0.9 25.8 11th 10.2 -0.3 5.0 8th 43.0 56.1 average 77%
Medina Research Centre 20.3 +0.1 25.0 11th 9.5 +0.5 4.7 28th 89.9 76.6 average 117%
Pearce RAAF 20.0 0.0 25.9 12th 8.7 0.0 4.6 28th 78.8 69.1 average 114%
Perth Airport 20.5 +0.4 26.2 12th 8.9 +0.1 3.8 28th 103.6 71.8 high 144%
Perth Metro* 20.5 +0.3 24.7 12th 9.4 0.0 4.9 29th 109.2 80.6 high 135%
Rottnest Island 18.7 0.0 21.7 12th 12.9 +0.1 10.3 28th 54.4 58.5 average 93%
Swanbourne 20.3 +0.7 24.5 30th 11.1 +0.2 6.8 28th 80.2 80.4 average 100%
South Coast (district 09A)
Albany 17.8 +0.6 25.1 12th 9.9 +0.7 6.0 24th 90.0 101.3 average 89%
Albany Airport 17.5 +0.2 24.2 12th 8.2 +0.2 2.5 24th 92.6 86.1 average 108%
Bridgetown 17.6 +0.1 21.7 11th 5.7 -0.2 0.8 10th 107.4 93.6 average 115%
Bridgetown Comparison 18.9 +0.6 23.5 11th 5.0 -0.7 1.1 10th 112.0 88.2 high 127%
Bunbury 18.8 +0.5 21.5 30th 8.2 -0.2 1.0 28th 96.8 79.0 average 123%
Busselton 19.1 +0.8 21.5 30th 8.6 -0.3 4.2 28th
Busselton Aero 19.0 +0.9 21.5 12th 7.4 -0.3 2.2 28th 79.0 80.9 average 98%
Cape Leeuwin 17.9 +0.9 21.4 1st 12.4 +0.6 8.8 28th 66.6 91.0 low 73%
Cape Naturaliste 18.6 +1.3 21.9 12th 10.8 +0.4 7.9 10th 71.0 76.2 average 93%
Collie East 18.5   23.8 11th 5.5   0.2 28th 109.6
Donnybrook 19.4 +0.6 23.6 12th 7.6 +0.5 1.5 28th 111.4 101.8 average 109%
Dwellingup 17.8 +0.6 23.0 11th 7.1 +0.7 1.1 28th 149.2 129.8 average 115%
Esperance 20.3 +1.0 27.8 12th 9.6 +0.1 6.3 23rd 76.0 61.6 average 123%
Esperance Aero 19.8 +1.2 26.8 25th 7.7 -0.7 4.2 11th 50.4 58.0 average 87%
Harvey 18.9 +0.5 23.0 11th 7.9 -0.6 2.4 28th 143.8 112.4 average 128%
Hopetoun North 20.0 -0.3 27.7 12th 9.4 +0.7 4.3 11th 40.2 50.9 average 79%
Jarrahwood 18.6 +0.6 22.1 11th 5.4 -0.6 0.2 11th 135.6 103.1 average 132%
Mandurah 19.5   23.6 30th 11.9   8.5 28th        
Manjimup 17.5 +1.0 23.0 11th 7.2 0.0 3.8 23rd 96.4 109.1 average 88%
North Walpole 17.4   22.3 11th 9.4   6.0 14th 117.2
Pemberton 17.8 +1.2 22.9 11th 9.4 +1.8 6.2 10th 129.5 128.2 average 101%
Rocky Gully 16.9 +0.6 22.0 12th 7.1 +0.1 3.6 30th 104.4 93.2 average 112%
Shannon 16.9 +0.6 21.7 11th 7.2 0.0 3.9 23rd 117.8 130.7 low 90%
Windy Harbour 17.9 +0.3 21.6 2nd 10.1 +0.7 4.8 10th 103.7 108.5 average 96%
Witchcliffe 17.8 +0.6 21.5 11th 8.5 -0.2 2.8 11th 142.2 113.2 average 126%
North Central (district 10)
Bencubbin 20.5 -0.4 25.9 12th 6.6 -0.5 2.0 29th 21.3 21.8 average 98%
Cunderdin Airfield 20.6 +0.1 27.1 12th 4.3 -0.4 -1.4 28th 29.8 26.3 average 113%
Merredin 20.7 +0.3 26.4 12th 5.8 -0.9 0.6 28th 32.6 25.7 high 127%
Northam 20.1 -0.3 26.2 12th 5.7 -1.1 0.3 28th 50.7 37.1 high 137%
York 19.7 -0.2 25.5 12th 3.9 -1.0 0.0 12th 48.3 37.2 high 130%
South Central (district 10A)
Beverley 20.0 -0.2 26.6 12th 5.6 -0.2 0.6 28th 43.8 36.0 high 122%
Brookton 18.8 -0.3 25.1 12th 4.9 -0.4 -0.8 28th 40.7 38.1 average 107%
Corrigin 19.1 0.0 24.9 12th 5.5 -0.2 0.9 29th 34.8 29.7 average 117%
Hyden 20.3 0.0 26.0 12th 5.4 -0.4 1.0 28th 38.1 27.7 high 138%
Jacup 19.0 +0.4 25.6 12th 6.5 +0.3 2.3 28th 40.6 47.5 average 85%
Katanning 17.2 -0.1 23.7 12th 5.9 -0.1 1.8 10th 62.0 50.0 high 124%
Katanning Comparison 17.6 -0.1 24.0 12th 6.2 -0.2 2.0 10th 58.6 46.5 high 126%
Lake Grace 18.8 -0.2 25.5 12th 6.2 -0.1 2.0 28th 32.0 28.4 average 113%
Lake Grace Comparison 18.8 -0.3 25.1 12th 6.4 -0.2 1.7 28th 29.4 30.3 average 97%
Narembeen 20.6 +0.2 26.2 12th 5.7 -0.4 2.0 29th 31.6 25.6 high 123%
Narrogin 17.8 +0.1 24.5 12th 5.9 -0.1 2.1 22nd 36.4 46.1 average 79%
Newdegate Research Station 18.6 0.0 24.7 12th 4.4 -0.5 -1.8 10th 41.4 34.1 average 121%
Ongerup 18.1 +0.3 24.4 12th 6.9 +0.4 2.6 28th 25.8 38.2 low 68%
Pingelly 18.3 0.0 24.8 12th 6.4 0.0 0.9 28th 45.0 40.5 average 111%
Ravensthorpe 19.9 +0.5 26.1 12th 8.5 +1.2 3.6 11th 37.4 41.6 average 90%
Wagin 18.1 0.0 24.2 12th 5.9 -0.2 1.8 10th 59.7 41.0 high 146%
Wandering 17.9 -0.3 23.8 12th 4.7 0.0 0.4 28th 72.8 54.1 high 135%
Eucla (district 11)
Balgair 26.8 +2.6 34.8 18th 6.6 -1.5 0.6 29th 7.2 15.8 low 46%
Balladonia 23.1 +0.8 31.2 18th 7.5 +0.7 2.5 24th 18.2 20.1 average 91%
Eucla 23.1 +1.9 35.7 18th 10.5 +1.4 4.3 4th 12.4 22.6 average 55%
Eyre 21.7 +0.6 35.9 18th 6.9 -0.8 -4.1 24th 21.0 23.8 average 88%
Forrest 25.0 +0.8 36.0 18th 7.5 -0.7 2.4 12th 1.8 16.2 low 11%
Red Rocks Point 21.5   34.4 18th 10.5   4.9 4th 18.4
South East (district 12)
Bulga Downs 24.7   31.0 14th 7.2   3.5 29th 11.0 7.7 high 143%
Kalgoorlie-Boulder Airport 22.6 +0.4 29.3 16th 8.2 +0.2 3.6 29th 12.2 14.2 average 86%
Laverton Aero 24.4 +0.1 33.0 25th 9.3 -1.1 3.8 11th 0.6 8.1 v low 7%
Leinster Aero 24.9 -0.5 31.7 16th 9.6 -1.0 5.2 4th 2.0 4.0 average 50%
Leonora 24.8 0.0 31.6 25th 9.0 -1.0 5.2 11th 7.2 8.9 average 81%
Leonora Aero 24.5   32.1 25th 8.9   4.0 11th 6.0
Munglinup West 20.3   26.7 12th 7.0   3.4 11th 27.2 38.7 average 70%
Norseman Aero 22.4 +0.2 28.1 25th 5.9 -0.3 -0.1 29th 9.0 23.7 low 38%
Salmon Gums Res.Stn. 21.5 +1.2 27.6 25th 5.0 -0.7 -3.4 11th 22.8 31.8 average 72%
Southern Cross Airfield 21.4 0.0 26.4 12th 4.8 -0.2 0.2 29th 19.0 22.0 average 86%
Yeelirrie                 1.1 4.6 average 24%
North East (district 13)
Balgo Hills 33.1 -0.6 38.5 26th 17.1 -1.5 11.3 12th 0 3.1 lowest 0%
Carnegie 28.1 -0.3 36.6 25th 9.7 -1.9 5.4 13th 0 4.0 lowest 0%
Giles Meteorological Office 28.0 +0.7 34.8 26th 11.7 -1.2 4.2 11th 1.4 11.3 average 12%
Telfer Aero 32.3 -0.4 39.0 25th 15.2 -1.2 9.5 13th 0 2.5 lowest 0%
Warburton Airfield 27.8 0.0 35.8 25th 9.4 -1.8 1.9 29th 0 5.8 lowest 0%
Wiluna 26.4 +0.1 32.5 16th 9.6 -0.3 3.5 26th 4.0 4.6 average 87%
Offshore Islands (district 200)
Christmas Island Aero 26.2 0.0 26.8 4th 22.3 +0.1 21.2 29th 6.4 45.9 low 14%
Cocos Island Airport 28.3 +0.1 29.1 16th 24.4 +0.5 22.1 21st 36.4 94.0 average 39%
Varanus Island 26.8 0.0 28.9 5th 20.6 -0.1 19.2 26th 0 0.4 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 11 am on Monday 3 October 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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