Monday, 1 November 2010 - Monthly Climate Summary for Perth - Product code IDCKGC11L0

Perth in October 2010: A warm and sunny month

  • Rainfall: Very much below average.
  • Maximum Temperature: Very much above average.
  • Minimum Temperature: Near average.

Details Extremes Records Summaries Important notes the top

Rainfall

October 2010 saw below average rainfall across the Perth area, with several sites receiving well below half their October average. A strong ridge of high pressure persisted over the south of WA for much of October 2010 causing the generally dry conditions in Perth, with the only rainfall coming from cold fronts during the middle and latter parts of the month.

Perth Metro recorded 20.6 mm of rainfall on 5 rain days in October, compared with the average of 52.4 mm on 9.1 rain days. Historically, October rainfall in Perth has ranged from 1.0 mm in 1969 to 199.9 mm in 1890. Last October (2009), Perth Metro recorded 6.8 mm on 5 days. The wettest day in October 2010 was 8.4 mm on the 21st.

2010 has been a particularly dry year in the southwest of WA, including the Perth region with Pearce RAAF, Gosnells City and Bickley all breaking their driest January to October records. Total rainfall for the ten months from January to October 2010 at Perth Metro was 474.8 mm recorded on 57 rain days, which is the third driest January to October period since records commenced in 1876, and the driest since the 445.4 mm in 2006, Perth Metro's driest year on record. The average for the January to October period is 817.6 mm on 101.4 rain days whilst the total for the same period last year was 590.0 mm on 104 days (ranked 10th driest on record). Perth Metro has also experienced its least number of rain days for the ten months (January to October) on record with 57, breaking the previous record of 80 days in 1969.

Maximum temperature

Daytime temperatures were well above average across the Perth area during October 2010, as a result of a strong ridge over the south of the state for much of the month, with several sites breaking their October mean daily maximum temperature records.

Hot days were experienced throughout the Perth area on the 8th, 18th and 26th, with most stations observing maximum temperatures in excess of 30 °C. Pearce RAAF observed the hottest day for October 2010, with 34.9 °C on the 26th.

Perth Metro's mean daily maximum temperature in October was 24.6 °C, which was the second warmest October on record behind the 25.8 °C observed in 1969 (records commenced in 1897). The average for October is 22.9 °C. Daily maxima during October 2010 ranged from a hot 33.8 °C on the 26th to a mild 19.3 °C on the 11th.

Minimum temperature

Minimum temperatures across the Perth area were close to normal during October 2010, with most metropolitan sites recording mean minima within 1 °C of their long-term mean. Jandakot Aerodrome experienced both the coldest night during October 2010, on the 29th with 2.6 °C, as well as the coolest nights on average, with a mean of 8.9 °C.

Perth Metro's mean daily minimum temperature in October was 10.6 °C, which was the coolest October since the 9.7 °C in 2005, but is close to the average of 11.2 °C for October. Daily minima ranged from a cool 6.3 °C on the 12th to a warm 17.8 °C on the 27th.

Wind

No severe wind gusts (a severe wind gust is a gust greater than 90 km/h) were recorded during October 2010, with the highest wind gust of 76 km/h observed at Rottnest Island early on the 14th in the wake of a cold front as a strong ridge developed over the south of the state.

Sunshine

Perth recorded average daily sunshine of 10.5 hours in October, which was the third sunniest October on record behind the 10.9 hours in 2000 and the 10.6 hours in 1978. The average daily sunshine for October is 9.6 hours.

Further information

Western Australia Climate Services Centre
Bureau of Meteorology
Phone (08) 9263 2222
Email climate.wa@bom.gov.au
Extremes in October 2010
Hottest day 34.9 °C at Pearce RAAF on the 26th
Warmest days on average 25.6 °C at Pearce RAAF
Coolest days on average 21.6 °C at Rottnest Island
Coldest day 16.3 °C at Bickley on the 21st
Coldest night 2.6 °C at Jandakot Aero on the 29th
Coolest nights on average 8.9 °C at Jandakot Aero
Warmest nights on average 14.3 °C at Rottnest Island
Warmest night 17.9 °C at Rottnest Island on the 27th
Wettest overall 31.8 mm at Jarrahdale
Wettest day 17.2 mm at Jarrahdale on the 21st
Highest wind gust 76 km/h at Rottnest Island on the 14th

Details Extremes Records Summaries Important notes the top

Record highest October mean daily maximum temperature
Mean daily maximum
temperature
for October 2010 (°C) 		Previous highest
for October		 Years of
record		 Average for
October
Medina Research Centre 24.3 23.8 in 2000 23 22.4
Jandakot Aero 24.8 24.2 in 2008 20 22.4
Swanbourne 23.6 23.2 in 2008 17 21.8
Bickley 22.5 22.3 in 2006 16 20.9
Gosnells City 25.5 25.1 in 2006 15 23.6

Details Extremes Records Summaries Important notes the top

Summary statistics for October 2010
Maximum temperatures
for October
(°C)		 Minimum temperatures
for October
(°C)		 Rainfall
for October
(millimetres)
Mean for
October
2010		 Diff
from
average		 Highest for
October
2010		 Mean for
October
2010		 Diff
from
average		 Lowest for
October
2010		 Total for
October
2010		 Average
for
October		 Rank of
October
2010		 Fraction of
October
average
Bickley 22.5 +1.6 31.2 26th 9.7 +0.3 5.0 11th 30.8 67.0 low 46%
Champion Lakes 24.1   32.9 26th 11.8   6.1 11th 15.2
Garden Island HSF 21.9   27.8 8th 12.7   7.0 18th 18.0
Gosnells City 25.5 +1.9 34.7 26th 11.6 +0.1 5.8 29th 15.0 46.7 v low 32%
Jandakot Aero 24.8 +2.4 33.4 26th 8.9 -0.5 2.6 29th 21.4 47.0 low 46%
Medina Research Centre 24.3 +1.9 32.3 26th 10.0 -0.2 4.5 29th 20.6 41.4 low 50%
Pearce RAAF 25.6 +2.4 34.9 26th 9.0 -1.1 3.0 29th 8.8 36.7 v low 24%
Perth Airport 25.1 +2.6 33.9 26th 9.7 -0.5 3.8 11th 27.4 44.5 low 62%
Perth Metro* 24.6 +1.7 33.8 26th 10.7 -0.5 6.3 12th 20.6 52.4 v low 39%
Rottnest Island 21.6 +1.4 28.2 18th 14.3 +0.6 10.7 15th 14.8 28.9 low 51%
Swanbourne 23.6 +1.8 29.1 8th 11.8 -0.2 7.2 12th 21.6 42.6 low 51%

Details Extremes Records Summaries Important notes the top

Daily rainfall
Central Coast (09)12345678910111213141516171819202122232425262728293031
Bickley 0.6 - - - - - - - - 7.0 2.0 - - - - - - - - - 13.2 - - - - - - 8.0 - - -
Champion Lakes - - - - - - - - - 4.6 0.8 - - - - - - - - - 6.0 - - - - - - 3.8 - - -
Garden Island HSF - - - - - - - - - 2.4 2.0 - - - - - - - - 0.2 10.8 0.2 - - - - - 2.2 0.2 - -
Gosnells City - - - - - - - - - - 1.1 - - - - - - - - - 9.2 - 0.1 - - - - 4.6 - - -
Jandakot Aero - - - - - - - - - 8.0 1.6 - - - - - - - - - 5.4 - - - - - - 5.6 0.8 - -
Jarrahdale - - 0.2 - - - - - - 7.2 2.8 - 0.2 - - - - - - - 17.2 - - - - 0.2 - 3.8 0.2 - -
Medina Research Centre - 0.4 - - - - - - - 5.2 2.4 - - - - - - - - - 11.2 - - - - - - 1.4 - - -
Mundaring 0.8 0.2 0.2 0.2 0.2



5.8 4.2








9.4





10.2 0.2

Pearce RAAF - - - - - - - - - 1.4 0.8 - - - -

- - - 3.4 - - - - - - 3.2 - - -
Perth Airport 0.2 - - - - - - - - 11.0 1.6 - - - - - - - - - 9.8 - - - - - - 4.6 0.2 - -
Perth Metro - - - - - - - - - 5.0 1.0 - - - - - - - - - 8.4 - - - - - - 5.8 0.4 - -
Rottnest Island - - - - - - - - - 3.4 0.4 - - - - - - - - 0.2 7.8 - - - - - - 3.0 - - -
Serpentine - 0.2 - - - - - - - 2.2 0.8 0.2 - - - - - - - - 15.8 0.2 - - - - - 2.2 0.4 - -
Swanbourne - - - - - - - - - 4.2 2.2 - - - - - - - - - 10.4 - - - - - - 4.6 0.2 - -

Most values are the precipitation in the 24 hours to 9 am on the day indicated. Days marked with »» are part of a longer accumulation, which is marked like this on the final day. Values over 100 mm have been rounded to the nearest whole millimetre. Days marked with - have a rainfall report of zero; days left blank have no rainfall report (which often indicates no rain fell).
This table is very wide; you may have to scroll sideways to see all the days, and you may need to set the paper to 'landscape' to print.

Details Extremes Records Summaries Important notes the top

Notes

A Monthly Climate Summary is prepared to list the main features of the weather in Perth 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 November 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 10 years of record, as they cannot then be calculated reliably.
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 10 years of data.

*Official Perth observations have been recorded at several different sites with varying instrumentation over the years, and these changes can affect the continuity of the climate record. For the current Mt Lawley site, the most significant changes of this kind relate to temperature and rain days.

For that reason, current mean temperature and rain-day data quoted here are based only on readings from the Mt Lawley site, which commenced observations in 1993. Sunshine recordings are from Perth Airport and for similar reasons current means use only Perth Airport data, which commenced in 1993.

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

Further information

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