Greater Perth in October 2021: very wet with cool daytime temperatures

October 2021 was very wet across Greater Perth. It was the wettest October on record at the Perth Metro site, and ranked the seventh-wettest October on record in Perth city's official records. Both mean maximum and minimum temperatures were below average for most sites.

Above average rainfall across Perth

  • October rainfall doubled or tripled the monthly average for most sites, with totals in the 70–130 mm range, to 150–160 mm in the Perth hills.
  • Several sites, mostly in the Perth hills, had their wettest October on record or wettest October for at least 20 years
  • Perth Metro recorded a monthly rainfall total of 122.8 mm, which was its wettest October on record at the current site, and also ranked the seventh-wettest October on record, and wettest since 1965 in Perth city's official records commencing in 1876.
  • Perth Metro recorded fourteen days of rain during October, which was above its October average of nine rain days; Perth Metro recorded daily rainfall at least 25 mm over two days (20th and 27th), which was a first for October at the Perth Metro site, and was only the fifth time in Perth city's official records. The last time the Perth city recorded a count of two days with at least 25 mm in October was 1965.

Below average daytime and night time temperatures

  • Mean maximum temperatures were mostly 1–2 °C below average, and mean minimum temperatures were generally 0.5–1.5 °C below average.
  • Perth Metro recorded a mean maximum temperature of 21.5 °C, which was 1.9 °C below average, and the second-lowest for October on record, behind the record low of 20.7 °C in 2005.
  • Perth Metro recorded a mean minimum temperature of 10.4 °C, which was 1.2 °C below average, and the third-lowest for October on record, and the lowest since 2005.

Perth Metro

  • Total rainfall for Perth Metro was 122.8 mm, which is 300% of the long-term average of 40.9 mm
  • The warmest day was 33.2 °C on the 15th, and the coolest day was on the 25th when the temperature reached 17.6 °C
  • The coldest morning was 4.7 °C on the 6th, and the warmest morning was on the 16th when the minimum temperature was 15.5 °C

 

Further information

Media
(03) 9669 4057

Extremes in October 2021
Hottest day 33.6 °C at Perth Airport on the 15th
Warmest days on average 22.1 °C at Millendon (Swan Valley)
Coolest days on average 18.7 °C at Bickley
Coldest day 13.8 °C at Bickley on the 26th
Coldest night 2.4 °C at Jandakot Aero on the 6th
Coolest nights on average 7.7 °C at Karnet
Warmest nights on average 13.4 °C at Rottnest Island
Warmest night 17.7 °C at Mandurah on the 16th
Warmest on average overall 16.6 °C at Rottnest Island
Coolest on average overall 13.5 °C at Karnet
Wettest overall 165.2 mm at Bickley
Wettest day 44.6 mm at Swanbourne on the 1st
Strongest wind gust 98 km/h at Rottnest Island on the 19th

Record highest October daily rainfall
New record
(mm)
Old
record
Years of
record
Anketell 27.8 on the 27th 27.6 on the 8th in 2007 20



Record highest October total rainfall
New record
(mm)
Old
record
Years of
record
Average for
October
Pearce RAAF 133.2 84.5 in 1965 68 37.2
Bickley 165.2 142.4 in 1977 53 67.2
Roleystone 153.8 144.0 in 1965 53 63.2
Maida Vale 107.8 104.4 in 1999 38 42.4
Huntly 156.0 155.4 in 1999 29 70.4
Perth Metro 122.8 96.4 in 1999 27 40.9
Swanbourne 129.4 106.2 in 1995 27 45.1
Pinjarra South 83.8 75.6 in 2002 21 37.3
Anketell 105.4 86.2 in 2007 20 45.4
Garden Island HSF 83.8 59.8 in 2005 20 29.3
Mandurah 75.2 71.2 in 2007 20 32.5

Highest October total rainfall for at least 20 years
Observed
(mm)
Most recent
higher
Average for
October
Mundaring 148.4 220.5 in 1955* 69.4
Chidlow 121.7 159.3 in 1955* 53.3
Wanneroo 114.7 122.5 in 1965* 47.3
Gidgegannup 130.6 148.7 in 1965* 51.7
Perth Airport 95.0 124.8 in 1971 43.3
Karragullen North 157.4 168.9 in 1965* 65.0
Jandakot Aero 125.8 138.6 in 1995 47.1

* note: there are gaps in the historical record at this site, so it is possible a higher value has gone unreported




Summary statistics for October 2021
Maximum temperatures
(°C)
Minimum temperatures
(°C)
Rainfall
(millimetres)
Mean for
October
2021
Diff
from
average
Highest for
October
2021
Mean for
October
2021
Diff
from
average
Lowest for
October
2021
Total for
October
2021
Average
for
October
Rank of
October
2021
Fraction of
October
average
Bickley 18.7 -2.6 30.6 15th 8.7 -1.1 4.5 6th 165.2 67.2 highest 246%
Garden Island HSF 19.5 -1.6 31.9 15th 12.4 -1.3 8.2 6th 83.8 29.3 highest 286%
Jandakot Aero 21.3 -1.7 32.7 15th 9.6 -0.3 2.4 6th 125.8 47.1 v high 267%
Karnet 18.9 -2.0 28.8 15th 7.7 -1.4 3.5 4th 118.4 75.5 high 157%
Mandurah 19.9 -2.1 31.8 15th 12.4 -1.1 7.3 6th 75.2 32.5 highest 231%
Millendon (Swan Valley) 22.1   33.0 15th 9.3   3.7 7th 76.2
Pearce RAAF 22.0 -1.6 33.1 15th 9.7 -0.5 3.5 7th 133.2 37.2 highest 358%
Perth Airport 21.8 -1.0 33.6 15th 9.7 -0.6 3.3 6th 95.0 43.3 v high 219%
Perth Metro 21.5 -1.9 33.2 15th 10.4 -1.2 4.7 6th 122.8 40.9 highest 300%
Rottnest Island 19.8 -0.8 25.8 15th 13.4 -0.7 9.9 6th 49.6 28.4 high 175%
Swanbourne 20.2 -2.1 33.0 15th 11.6 -0.9 6.3 6th 129.4 45.1 highest 287%

Daily maximum temperatures for October 2021
12345678910111213141516171819202122232425262728293031
Bickley15.415.515.016.615.416.118.017.120.317.015.420.421.430.620.818.923.416.815.716.519.523.128.514.213.814.616.818.922.124.0
Garden Island HSF19.218.916.919.916.217.119.517.617.421.519.816.116.822.231.921.521.122.420.118.619.519.120.923.416.416.817.016.919.022.218.5
Jandakot Aero19.819.818.720.118.018.019.919.619.922.421.318.121.023.932.722.221.924.021.619.820.321.725.028.716.917.718.219.221.224.323.1
Karnet17.015.915.517.014.915.617.216.917.520.717.215.119.221.828.818.623.023.016.416.019.523.027.414.715.916.318.522.522.3
Mandurah19.418.418.218.517.118.119.219.219.620.318.417.519.021.931.822.120.820.819.818.618.720.421.923.617.516.417.918.821.721.6
Millendon (Swan Valley)20.120.319.220.118.918.721.321.020.622.621.118.722.824.133.023.322.426.821.519.620.622.926.131.617.317.418.120.421.925.425.8
Pearce RAAF19.220.019.020.118.718.420.920.320.123.221.018.122.424.233.122.622.626.921.721.121.322.226.332.017.917.518.719.921.825.525.8
Perth Airport19.619.919.620.019.318.820.420.420.422.620.918.421.524.333.622.321.925.521.019.520.322.625.930.717.317.518.620.022.125.224.4
Perth Metro19.520.018.920.418.418.620.120.220.122.220.417.820.924.533.222.122.324.320.820.420.422.225.928.617.617.918.120.021.124.923.9
Rottnest Island19.319.318.720.217.517.620.219.018.420.720.316.817.620.925.820.921.322.220.220.119.819.322.224.917.217.017.817.518.821.819.3
Swanbourne19.719.618.019.817.417.519.618.818.821.620.216.918.323.133.021.121.122.420.019.520.320.023.524.117.217.617.718.419.922.119.9
Values are the maximum temperature, usually in the 24 hours from 9 am on the day indicated,
and typically occurred in the afternoon of that day.
Temperatures coloured according to their difference
from the long-term average for the period
-10.0 -9.0 -8.0 -7.0 -6.0 -5.0 -4.0 -3.0 -2.0 -1.0 0.0 +1.0 +2.0 +3.0 +4.0 +5.0 +6.0 +7.0 +8.0 +9.0 +10.0 °C Grey outline marks highest
and lowest for the period

Daily minimum temperatures for October 2021
12345678910111213141516171819202122232425262728293031
Bickley13.37.77.65.78.44.56.59.56.55.910.55.55.87.29.914.312.58.512.110.310.59.68.812.311.17.08.16.07.07.29.9
Garden Island HSF16.313.114.09.912.48.29.013.511.610.314.29.810.411.413.315.017.210.214.914.815.212.612.215.214.29.210.311.210.710.914.0
Jandakot Aero14.58.712.64.410.12.43.412.05.96.811.67.44.69.913.014.416.16.314.413.414.410.98.39.713.87.810.15.38.710.17.9
Karnet6.88.83.57.13.69.16.86.19.44.24.18.011.35.512.511.09.88.19.09.811.56.34.86.56.99.5
Mandurah16.212.213.610.212.37.310.812.810.79.814.68.88.711.114.217.716.712.515.014.515.412.412.015.013.510.410.510.510.411.113.2
Millendon (Swan Valley)12.99.47.84.69.94.73.712.76.27.010.97.24.410.213.114.412.77.114.713.59.911.88.69.813.37.49.35.58.110.87.3
Pearce RAAF13.49.19.96.411.36.43.512.76.17.211.08.13.910.114.313.614.17.315.213.212.611.18.89.613.18.57.56.17.611.18.0
Perth Airport14.89.311.16.29.73.34.012.65.26.611.17.24.411.013.815.512.88.814.713.411.510.58.510.313.78.010.15.28.011.07.4
Perth Metro14.510.713.46.110.84.75.013.36.77.712.48.66.310.313.015.513.78.714.913.514.69.510.614.28.410.46.78.810.69.3
Rottnest Island16.612.613.612.213.59.912.114.113.011.715.010.911.112.214.917.616.014.615.513.614.913.313.515.914.410.710.711.711.412.314.5
Swanbourne15.411.913.68.611.56.37.713.49.19.513.58.58.011.214.415.515.910.414.513.715.112.811.512.913.98.811.08.810.310.511.1
Values are the minimum temperature, usually in the 24 hours to 9 am on the day indicated,
and typically occurred that morning.
Temperatures coloured according to their difference
from the long-term average for the period
-10.0 -9.0 -8.0 -7.0 -6.0 -5.0 -4.0 -3.0 -2.0 -1.0 0.0 +1.0 +2.0 +3.0 +4.0 +5.0 +6.0 +7.0 +8.0 +9.0 +10.0 °C Grey outline marks highest
and lowest for the period

Daily rainfall for October 2021
12345678910111213141516171819202122232425262728293031
Anketell 8.0 8.4 9.2 0.1 3.5 - - 1.1 - - - 7.4 - - - - - - 11.1 12.3 4.1 0.5 - - 4.2 7.5 27.8 0.2 - - -
Araluen 22.0 15.0 7.0 4.0 2.0 - 4.0 - - - 6.0 - - - - - - - 11.5 26.0 6.4 0.6 - - - 5.0




Bickley 7.8 22.6 10.6 - 4.0 - - 1.6
- - 10.6 - - - - - - 14.4 33.6 7.6 1.0 - - 6.2 4.2 33.2 7.8 - - -
Bungendore 26.6 20.8 1.4 0.2 3.8 - 0.2 3.0 - - - 11.6 0.2 - - - - - 12.8 21.4 8.2



4.0 38.2 1.0 0.2 - -
Chidlow 8.2 17.8 2.8 9.0 - - 1.2 - - - 6.8 - - - - - - 9.1 28.6 7.6 - - 3.2 4.4 21.0 2.0 - -
Garden Island HSF 8.8 1.8 3.6
5.2 - - 1.4 0.2 - - 4.8 - -
- - - 10.4 7.6 3.0 2.8 - - 4.0 10.6 19.6 - - - -
Gidgegannup 4.2 23.4 7.4 - 4.8 0.2 - 4.6 - - - 5.4 - - - - - - 13.0 28.0 7.8



4.6 25.0 2.2


Gosnells City
- 10.4 - - - - - - -




- - - - - - - - -




- -
Huntly 9.0 8.2 13.0 - 4.0 2.0 - 2.5 - - - 16.2 - - - - - - 13.0 31.0 15.0 3.8 0.1 - 8.0 4.6 25.4 - 0.2 - -
Jandakot Aero 29.0 13.4 9.6 - 3.4 - - 1.0 - - - 4.8 - - - - - - 11.6 6.2 1.8 0.4 - - 3.0 3.4 37.2 1.0 - - -
Jarrahdale 12.0 18.0 12.2 - 3.4 - 0.2 2.0 - 0.2 - 9.8 - 0.2 - - - - 13.8 21.0 10.0



6.2 21.8 0.4 0.2 - -
Karnet 10.9 4.6 6.7 - 4.9 0.1 - 3.2 - - - 13.6 - - -

- 14.1 21.1 11.4 2.8 - - 3.6 4.8 16.6 - - -
Karragullen North 7.4 24.6 7.4 - 4.4 - - 2.0 - - - 10.6 - - - - - - 11.6 32.8 5.0 - - - 6.0 5.4 36.2 4.0


Maida Vale 8.8 15.2 - - 3.4 - - 3.0 - - - 5.4 - - - - - - 8.4 21.0 3.0 - - - 3.2 3.4 28.6 4.4


Mandurah 1.0 7.8 5.0 - 2.0 0.2 - 0.2 - - - 7.2 - - - - - - 12.2 5.8 4.2 1.0 0.2 - 3.0 3.6 21.8 - - - -
Millendon (Swan Valley) 0.8 0.8 0.8 0.4 1.2 0.8

- - - 4.2 0.2 - - - - - 8.2 18.4 5.8 0.4 - - 5.0 1.6 20.4 7.0 0.2 - -
Mount Solus 7.2 10.6 12.4 - 3.2 0.2 - 3.0 - - - 11.6 - 0.2 - - 0.2 - 11.8 28.2 13.8



3.2 17.6 1.4 0.2 - -
Muchea 1.2 17.0 4.0 - 6.2 0.2 - 2.4 - - - 2.6 0.2 - - - - - 11.4 22.6 6.0



4.6 31.0 4.0 - - -
Mundaring 5.0 21.6 6.0 0.2 5.4 - - 2.6 - - - 9.2 - - - - - - 11.4 41.4 9.6 0.6 - - 8.2 5.0 22.2



Pearce RAAF 1.0 22.6 4.0 0.2 4.4 0.4 - 2.0 0.2 - - 4.2 - - - - - - 12.0 29.2 8.4 - - - 2.4 4.6 32.4 5.2 - - -
Perth Airport 3.2 12.2 5.4 - 3.2 0.2 - 1.2 - - - 6.2 - - - - - - 7.8 24.0 4.2 0.6 - - 2.0 3.6 18.4 2.8 - - -
Perth Metro 8.4 15.4 5.6 - 4.2 - - 4.6 - - - 7.4 - - - - - - 11.2 26.4 1.6 2.2 - - 2.6 5.4 26.8 1.0 - - -
Pinjarra South 6.4 4.8 5.6 - 3.6 - - 0.6 0.2 - - 4.6 0.2 - - - - - 13.0 12.0 7.2



1.0 24.6 - - - -
Roleystone 14.0 25.2 7.8 - - - - 6.6 - - - 6.6 - - - - - - 11.8 24.2 4.8 - 8.2 3.6 41.0



Rottnest Island 1.8 1.4 3.2 - 1.2 0.2 - 0.8 0.2 - - 2.8 0.2 - - - - - 11.4 8.6 0.8 4.4 - - - 1.6 10.2 0.2 - 0.6 -
Serpentine 4.0 9.6 10.8 - 3.8 0.2 - 1.4 - - - 7.6



- - 5.8 11.4 0.8



- - 0.8 - - -
Swanbourne 44.6 10.2 2.4 - 4.0 - - 5.0 - - - 5.2 - - - - - - 13.0 17.0 2.4 2.4 - - 1.0 6.4 14.2 1.6 - - -
Tamala Park (Mindarie) 1.2 18.2 3.2 - 7.6 - - 2.6 - - - 5.6 0.1 - - - - - 10.6 17.1 3.6 2.1 - - 2.2 8.6 14.6 2.4


Wanneroo 10.0 - - 14.0 6.2 0.1 - 4.6 - - - 4.6 - - - - - - 10.2 19.0 5.0 - 15.6 25.0 0.4 - - -
Werribee 0.8 12.6 6.4 - 2.6 0.2 - 1.0 - - - 3.8 0.2 - - - - - 8.8 28.2 5.4



2.0 22.2 1.6 - - -
Whiteman Park 6.0 - - - 9.6 - - - - - - 2.8 - - - - - - 8.8 22.9 4.6 - 4.0 - 21.0 3.4 -

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 shown 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).
Rainfalls coloured
according to the amount
0 1.0 5.0 10.0 15.0 25.0 50.0 100 150 200 300 400 600 millimetres

Notes

The Monthly climate summary, generally published on the first working day of each month, lists the main features of the weather in Greater Perth using the most timely and accurate information available on the date of publication; it will generally not be updated. More extensive discussion of significant weather events, along with later information and data that has had greater opportunity for quality control, will be presented in the Monthly Weather Review.

This summary includes data from observing sites in or near the Greater Perth “Greater Capital City Statistical Area” (GCCSA). The Australian Bureau of Statistics designed the GCCSAs to “include the population within the urban area of the city, as well as people who regularly socialise, shop or work within the city, and live in small towns and rural areas surrounding the city. It is important to note that GCCSAs do not define the built up edge of the city. They provide a stable definition for these cities and are designed for the output of a range of social and economic survey data.

This statement has been prepared based on information available at 12 pm on Monday 1 November 2021. Some checks have been made on the data, but it is possible that results will change as new information becomes available.

In some situations, some or all of the rainfall is in the form of hail or snow. In these cases the totals given are for the water equivalent: the depth of liquid water that results from melting any frozen precipitation. There can be significant 'undercatch' of snow in strong winds, meaning the true precipitation can be higher than that reported.

Averages for individual sites 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.

Where temperature area averages are mentioned, they are derived from the ACORN-SAT dataset.

Further information

Media
(03) 9669 4057

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