Perth in January 2011: An above average month

  • Rainfall: Above average.
  • Maximum temperature: Above average.
  • Minimum temperature: Above average.

Rainfall

January 2011 saw above to very much above average rainfall across the Perth metropolitan area, with monthly totals ranging from 16.6 mm at Swanbourne to 43.2 mm at Perth Airport. Several stations, including Perth Airport, Perth Metro, Gosnells City and Serpentine, observed their wettest January in over 10 years.

Moderate rainfall was received across the city in the 24 hours to 9am on the 6th due to a cold front and middle level cloudband, with daily totals generally in the 10 to 20 mm range, grading to 20 to 30 mm in the hills.

A line of severe thunderstorms, originating from the north, crossed the Perth Metropolitan area during the afternoon of 29 January causing moderate rainfall at several locations. The highest daily rainfall totals in the 24 hours to 9am on the 30th were 20.6 mm at Perth Airport and 14.0 mm at Champion Lakes, while other sites received less than 10.0 mm of rainfall.

Ex-Tropical Cyclone Bianca passed through the Perth region on 30 January 2011, however the low had weakened considerably and only light showers and drizzle were reported overnight on the 30th.

Perth Metro recorded 30.2 mm of rainfall on 6 rain days in January 2011, which was the wettest January since 139.0 mm was recorded on 7 rain days in 2000, the wettest January on record for Perth Metro. The wettest day in January 2011 at Perth Metro was 13.6 mm on the 6th, which was the wettest January day for three years since 13.6 mm was recorded on 3 January 2007. The average rainfall for January at Perth Metro is 9.5 mm on 2.1 rain days, whilst last January Perth Metro recorded nil rainfall.

Maximum temperature

Daytime temperatures were above average across the Perth area during January 2011, with most sites 1 to 2 °C above their January average.

2011 began with heatwave conditions (three or more days of 35.0 °C or more) at many sites around the Perth area from 1 to 4 January with Perth Airport, Pearce RAAF and Gosnells City all observing maximum temperatures of just over 40.0 °C on the 2nd. Another heatwave was experienced in the Perth region during the latter part of the month, from the 27th to the 30th, with several sites observing multiple days over 40 °C. Gosnells City observed the hottest day of January 2011 during this event with 42.0 °C on the 29th.

Perth Metro's mean daily maximum temperature in January 2011 was 32.5 °C, which was the equal 7th hottest January on record for Perth Metro. The hottest January on record was 34.4 °C in 1962; while last year (2010), Perth Metro recorded the second hottest January on record with 33.4 °C. The average for January at Perth Metro is 30.8 °C. Daily maxima during January 2011 at Perth Metro ranged from a very hot 40.4 °C on the 29th, to a mild 22.6 °C on the 24th, which was the coolest January day since the 19.7 °C on 3 January 2007.

Minimum temperature

Minimum temperatures across the Perth area were above average during January 2011, with most sites 1 to 2 °C above their January average. Bickley and Swanbourne both broke their highest January mean daily minimum temperature records.

Very warm overnight conditions were experienced from the 28th to 30th, with daily minima in the mid to high 20's due to very hot days and high humidity. Medina Research Centre broke its highest January daily minimum temperature record with 27.5 °C on the 28th, which was also the highest overnight temperature in the Perth area during January 2011.

Perth Metro's mean daily minimum temperature in January 2011 was 19.5 °C, which was the warmest January on record at the Mount Lawley site (observations commenced in 1994). The previous January record at the Mt Lawley site was 18.9 °C in 2008 and 2010. The long term Perth Metro record for January was 20.9 °C set in 1978 while the average for January is 17.8 °C. Daily minima in January 2011 ranged from a mild 13.1 °C on the 25th to a hot 26.1 °C on the 28th.

Wind and sunshine

No severe winds (gust greater than or equal to 90 km/h) were observed in the Perth area during January 2011, with the strongest gust the 85 km/h at Bickley on the 29th. Wind conditions across the Perth area were close to normal during January 2011.

Perth recorded an average daily sunshine of 10.8 hours in January 2011, which was below the average of 11.6 hours and the least sunniest January since the 10.1 hours in 2006.

Further information

Media
(03) 9669 4057
Enquiries

Extremes in January 2011
Hottest day 42.0 °C at Gosnells City on the 29th
Warmest days on average 34.3 °C at Gosnells City
Coolest days on average 27.8 °C at Rottnest Island
Coldest day 20.6 °C at Bickley on the 24th
Coldest night 10.3 °C at Jandakot Aero on the 25th
Coolest nights on average 16.8 °C at Bickley
Warmest nights on average 20.1 °C at Rottnest Island
Warmest night 27.5 °C at Medina Research Centre on the 28th
Wettest overall 43.2 mm at Perth Airport
Wettest day 28.2 mm at Bickley on the 6th
Highest wind gust 85 km/h at Bickley on the 29th

Highest total January rainfall for at least 10 years
Total rainfall
for January 2011 (mm)
Most recent January
at least this wet
Years since
wetter
Average for
January
Serpentine 35.4 44.9 in 1960 32 9.0
Gosnells City 29.6 141.6 in 2000 11 11.9
Perth Airport 43.2 102.4 in 2000 11 9.4
Perth Metro* 30.2 139.0 in 2000 11 16.4



Record highest January daily minimum temperature
Highest daily minimum
temperature
in January 2011 (°C)
Previous warmest
for January
Years of
record
Average for
January
Medina Research Centre 27.5 on the 28th 27.4 on the 23rd in 1989 23 16.7



Record highest January mean daily minimum temperature
Mean daily minimum
temperature
for January 2011 (°C)
Previous warmest
for January
Years of
record
Average for
January
Bickley 16.8 16.3 in 2009 17 15.1
Swanbourne 19.3 19.0 in 1995 17 17.9


Summary statistics for January 2011
Maximum temperatures
for January
(°C)
Minimum temperatures
for January
(°C)
Rainfall
for January
(millimetres)
Mean for
January
2011
Diff
from
average
Highest for
January
2011
Mean for
January
2011
Diff
from
average
Lowest for
January
2011
Total for
January
2011
Average
for
January
Rank of
January
2011
Fraction of
January
average
Bickley 31.7 +1.1 38.1 28th 16.8 +1.7 11.3 25th 36.6 17.2 high 213%
Champion Lakes 32.7   39.5 29th 20.0   13.6 25th 35.2
Garden Island HSF 28.9   37.5 10th 19.9   15.6 25th 20.6 10.3 high 200%
Gosnells City 34.3 +1.3 42.0 29th     12.5 25th 29.6 11.9 high 249%
Jandakot Aero 33.0 +1.9 40.6 29th 18.0 +1.5 10.3 25th 31.4 14.6 high 215%
Medina Research Centre     39.4 28th 18.8 +2.1 12.4 25th 21.6 11.4 high 189%
Perth Airport 33.8 +2.2 41.8 29th 19.0 +2.1 11.2 25th 42.6 9.4 v high 453%
Perth Metro* 32.5 +1.7 40.4 29th 19.5 +1.7 13.1 25th 30.2 9.5 v high 318%
Rottnest Island 27.8 +1.6 34.5 12th 20.1 +1.2 16.4 25th 33.8 13.4 high 252%
Swanbourne 31.5 +2.1 38.8 2nd 19.3 +1.4 13.2 25th 16.6 16.9 high 98%

Daily maximum temperature
Central Coast (09)12345678910111213141516171819202122232425262728293031
Bickley 33.6 37.3 33.3 35.4 26.0 24.3 23.6 29.7 34.3 33.3 32.0 34.2 34.3 23.6 28.5 33.7 34.7 33.0 31.7 30.0 33.4 35.0 28.3 20.6 26.8 30.3 37.4 38.1 37.9 36.1
Champion Lakes35.539.333.336.827.025.425.131.336.235.833.936.433.425.128.936.234.933.932.230.434.135.128.4 21.9 26.830.139.238.3 39.5 36.6
Garden Island HSF28.835.335.129.126.825.224.728.434.3 37.5 35.434.232.923.125.732.227.826.426.224.227.125.524.7 20.8 22.625.831.332.628.935.1
Gosnells City 36.8 40.8 35.9 38.7 28.7 27.1 26.5 32.0 37.7 37.4 36.0 38.3 35.9 26.5 30.0 37.5 37.4 34.8 33.0 31.2 35.5 36.1 29.9 23.2 28.0 31.5 40.7 40.0 42.0 38.6
Jandakot Aero 37.3 38.9 35.6 36.2 27.8 26.1 26.0 30.7 37.1 37.1 35.3 36.9 34.8 26.0 27.7 36.3 34.5 32.6 31.2 29.2 33.8 34.0 28.0 22.6 26.6 29.9 38.9 39.0 40.6 38.6
Medina Research Centre 37.5 39.2 34.2 27.2 26.0 25.4 29.9 36.4 37.9 35.7 37.7 35.2 25.3 27.5 37.0 32.6 32.7 30.4 28.4 30.8 32.1 26.3 22.5 24.9 27.8 37.0 39.4 37.6 38.9
Pearce RAAF 36.5 40.3 35.8 38.9 31.3 27.4 26.8 32.9 37.3 37.2 35.4 37.2 38.4 27.0 30.7 36.6 39.3 35.9 35.7 31.4 37.2 34.3 25.5 28.6 32.6 40.5 41.8 41.0 40.7
Perth Airport 36.8 40.3 36.4 38.0 29.0 25.9 26.2 32.2 37.4 36.5 35.2 37.2 36.4 26.0 29.3 36.8 37.1 33.5 32.1 29.7 35.3 33.6 31.2 24.6 27.1 30.8 40.0 40.4 41.8 38.4
Perth Metro 36.4 39.0 34.7 36.5 28.5 25.8 25.1 30.5 36.6 36.4 34.7 36.9 34.1 25.1 27.9 36.3 36.2 32.4 30.5 27.7 34.2 33.2 29.5 22.6 25.8 28.4 37.8 38.1 40.4 37.6
Rottnest Island 26.7 29.7 31.7 30.8 26.0 24.5 24.5 25.9 33.2 34.1 31.6 34.5 29.8 24.2 23.5 28.9 28.3 25.8 26.4 24.2 26.0 26.2 24.0 21.1 23.5 24.6 32.5 32.4 29.5 29.8
Swanbourne 33.8 38.8 33.5 31.9 27.8 25.4 25.5 30.9 37.4 38.3 36.1 38.2 31.8 25.5 28.4 35.8 30.8 29.8 28.9 26.6 31.0 29.0 27.8 23.4 25.2 28.1 36.4 36.2 37.6 35.6

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.

Daily minimum temperature
Central Coast (09)12345678910111213141516171819202122232425262728293031
Bickley 13.5 14.9 21.0 19.9 22.5 15.9 14.1 13.9 16.1 18.3 14.6 15.5 20.5 13.6 12.4 13.8 18.2 15.5 15.3 13.1 16.7 19.4 19.7 16.6 11.3 14.0 16.6 23.1 21.4 20.2 19.8
Champion Lakes17.218.6 25.6 23.726.918.617.617.420.222.918.519.623.717.715.517.522.419.119.517.020.319.019.716.9 13.6 15.119.4 25.4 24.123.822.2
Garden Island HSF17.419.123.520.823.020.518.817.419.723.518.921.020.217.816.717.817.118.920.018.020.421.220.716.8 15.6 18.019.7 24.2 23.523.921.5
Gosnells City 17.4 19.0 24.2 24.4 25.2 18.8 18.1 17.4 19.3 20.3 23.2 20.3 16.0 17.5 23.3 19.3 19.4 19.5 20.5 20.8 20.2 12.5 13.7 15.5 26.5 26.0
Jandakot Aero 16.8 18.4 24.1 20.1 22.9 16.8 17.6 14.9 17.2 22.6 18.1 19.5 17.5 16.2 11.3 16.9 18.7 15.8 14.8 14.6 17.1 15.6 19.4 16.7 10.3 10.8 17.7 26.6 23.5 23.6 21.8
Medina Research Centre 16.9 19.1 22.3 24.7 18.8 18.4 17.8 18.7 23.2 18.8 20.4 19.4 17.2 13.2 18.4 17.0 17.7 17.2 13.4 18.0 16.2 19.6 15.0 12.4 14.1 18.7 27.5 23.9 24.1 21.9
Pearce RAAF 17.1 18.5 26.5 22.0 24.0 19.2 15.8 14.4 18.5 23.0 18.7 21.1 21.2 16.4 14.0 17.5 19.2 15.8 15.2 15.3 16.8 19.8 11.7 11.5 17.3 26.0 22.8 24.0 22.3
Perth Airport 17.2 18.7 25.4 21.7 23.3 18.5 17.3 16.7 18.4 22.5 18.3 19.4 20.0 16.0 13.4 17.3 21.0 18.9 17.8 16.2 18.0 16.0 20.2 19.1 11.2 11.3 17.7 26.9 23.4 23.5 22.7
Perth Metro 17.4 18.7 25.2 22.3 23.8 18.6 17.5 17.1 18.8 22.2 18.4 19.5 19.8 18.0 15.0 17.5 20.0 18.6 18.7 16.4 19.1 18.2 20.4 18.5 13.1 15.5 18.5 26.1 23.7 23.7 22.8
Rottnest Island 17.5 19.0 21.9 21.1 23.1 19.2 18.0 18.3 20.5 22.9 19.6 21.3 21.9 18.8 17.4 18.3 21.4 19.6 20.5 18.5 20.8 21.0 19.8 16.8 16.4 18.8 20.1 23.4 22.6 23.3 20.4
Swanbourne 16.9 18.7 23.0 22.6 24.3 19.4 17.1 15.5 18.1 23.1 19.2 20.4 22.3 17.5 13.9 17.4 21.1 17.4 18.2 15.7 18.3 18.6 19.7 18.0 13.2 14.7 18.9 25.2 22.9 24.0 22.5

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.

Daily rainfall
Central Coast (09)12345678910111213141516171819202122232425262728293031
Bickley - - - - 0.2 28.2 0.2 0.2 - - - - - - - - - - - - - - - - 0.2 - - - 3.8 1.0 2.8
Champion Lakes - - - - - 17.8 0.6 - - - - - - - - - - - - - - - 1.6 0.2 - - - - - 14.0 1.0
Garden Island HSF - - - - - 6.2 - 0.2 - - - - - - - - - - - - - - 1.2 3.4 1.4 - - - 4.0 1.2 3.0
Gosnells City - - - - 1.2 9.1 - - - - - - - - - - - - - - - - - - 0.2 - - - - 17.5 1.6
Jandakot Aero - - - - 0.2 20.2 0.2 - - - - -
- - - - 2.2 - - - - 4.2 - 0.4 - - - 1.0 1.0 2.0
Jarrahdale - - - - - 24.6 0.2 - - - - - - - - - - - - - - - 6.8 1.0 2.0 - - - 0.4 5.6 2.2
Medina Research Centre - - - - 1.6 9.8 0.8 - - - - - - - - - - - - - - - 3.6 1.2 - 0.6 - - 1.2 0.4 2.4
Mundaring


5.2 3.4 19.2 0.2















0.2


2.8 0.4 1.0 3.0
Pearce RAAF - - - - 0.2 6.0 - - - - - - - - - - - - - - -

- - - - 0.6 0.2 2.4 1.4
Perth Airport - - - - 4.2 16.0 - - - - - - - - - - - - - - - - - - - - - - - 20.8 1.6
Perth Metro - - - - 2.8 13.6 - - - - - - - - - - - - - - - - 1.2 - - - - - 0.2 7.8 4.6
Rottnest Island - - - - - 18.6 - - - - - - - - - - - - - - - - 0.8 1.4 - - - - 8.4 4.0 0.6
Serpentine - - - - - 19.2 0.2 - - - - - - - - - - - - - - - 3.2 2.8 2.6 - - - 0.2 6.0 1.2
Swanbourne - - - - 0.6 12.2 - - - - - - - - - - - - - - - - 1.8 - - - - - 0.6 0.2 1.2

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.


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 12 pm on Monday 31 January 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 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 minimum 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

Media
(03) 9669 4057
Enquiries