Greater Perth in April 2020: dry with hot days in early April

April was dry and temperatures were generally mild across Greater Perth, apart from few hot days in early April including the record breaking day on the 11th. Monthly rainfall was well below average despite there were at least eight days of light rainfall late in April.

Below average rainfall

  • Monthly rainfall totals were less than 10 mm along the coast and in offshore islands, about 10–15 mm in the coastal plain sites, and up to 20–25 mm in the Perth hills
  • Monthly rainfall was 20–40% of April average across Perth
  • The wettest day was on the 19th as a cold front produced moderate rainfall at several sites in the Perth hills
  • Perth Metro recorded 13.2 mm, which was its seventh–driest April on record, and driest since 2017 (nil rainfall), since records commenced in 1993

Above average daytime and overnight temperatures

  • Mean maximum temperatures ranged in the mid–to–high twenties, and about 0.4–1.5 °C above average, across Greater Perth
  • In early April, Perth experienced a few days of temperatures over 30 °C from the 6th till the 11th, when temperatures climbed even further to the low forties in inland northern suburbs, and multiple April temperature records broken
  • Perth Metro had five consecutive days with temperature of 32 °C or higher between the 7th and 11th, which was a record for April; the previous record was four consecutive days and occurred on four occasions
  • Perth Metro recorded 39.5 °C on the 11th, a new April temperature record, and 2.2 °C higher than its previous record; Perth city previously had only recorded 37 °C or above twice in April (37.6 °C on the 9th in 1910 and 37.1 °C on the 3rd in 1971 at Perth Regional Office)
  • Mean minimum temperatures ranged in the teens, and 0.5–1.0 °C above average, across Greater Perth
  • The mean minimum temperature at Perth Metro was 14.7 °C, which was its warmest April since 2016 (15.3 °C), and equal fifth-warmest April on record

Perth Metro

  • Total rainfall for Perth Metro was 13.2 mm, which is 38% of the long-term average of 35.2 mm
  • The mean daily maximum temperature for Perth Metro was 26.4 °C, which is 0.5 °C above the long-term average of 25.9 °C
  • The warmest day was 39.5 °C on the 11th, and the coolest day was on the 28th when the temperature reached 20.8 °C
  • The mean daily minimum temperature for Perth Metro was 14.7 °C, which is 0.9 °C above the long-term average of 13.8 °C
  • The coldest morning was 8.9 °C on the 3rd, and the warmest morning was on the 12th when the minimum temperature was 21.7 °C

Further information

Media
(03) 9669 4057

Extremes in April 2020
Hottest day 40.7 °C at Pearce RAAF on the 11th
Warmest days on average 28.0 °C at Pearce RAAF
Coolest days on average 24.0 °C at Bickley
Coldest day 18.3 °C at Karnet on the 28th
18.3 °C at Bickley on the 30th
Coldest night 6.2 °C at Jandakot Aero on the 3rd
6.2 °C at Karnet on the 29th
Coolest nights on average 12.6 °C at Karnet
Warmest nights on average 17.9 °C at Rottnest Island
Warmest night 22.4 °C at Pearce RAAF on the 7th
22.4 °C at Rottnest Island on the 11th
22.4 °C at Swanbourne on the 11th
22.4 °C at Mandurah on the 12th
Warmest on average overall 21.1 °C at Rottnest Island
Coolest on average overall 18.7 °C at Bickley
Wettest overall 25.0 mm at Jarrahdale
Driest overall 6.0 mm at Pinjarra South
Wettest day 13.4 mm at Jarrahdale on the 19th
Strongest wind gust 72 km/h at Ocean Reef on the 19th

Record highest April temperature
New record
(°C)
Old
record
Years of
record
Average for
April
Perth Airport 39.6 on the 11th 37.7 on the 8th in 2013 76 25.6
Pearce RAAF 40.7 on the 11th 39.4 on the 8th in 2013 63 26.5
Karnet 36.6 on the 11th 35.0 on the 8th in 2013 54 23.3
Rottnest Island 35.2 on the 11th 33.1 on the 10th in 2009 31 23.7
Jandakot Aero 39.2 on the 11th 37.0 on the 8th in 2013 30 25.8
Bickley 36.5 on the 11th 35.1 on the 8th in 2013 27 23.6
Gosnells City 39.5 on the 11th 38.5 on the 8th in 2013 27 26.5
Perth Metro 39.5 on the 11th 37.3 on the 8th in 2013 27 25.9
Swanbourne 37.3 on the 11th 35.9 on the 6th in 2005 27 25.3



Summary statistics for April 2020
Maximum temperatures
(°C)
Minimum temperatures
(°C)
Rainfall
(millimetres)
Mean for
April
2020
Diff
from
average
Highest for
April
2020
Mean for
April
2020
Diff
from
average
Lowest for
April
2020
Total for
April
2020
Average
for
April
Rank of
April
2020
Fraction of
April
average
Bickley 24.0 +0.4 36.5 11th 13.5 +0.9 6.6 29th 18.2 54.7 low 33%
Garden Island HSF 24.4 +0.6 37.1 11th 17.0 +0.9 11.3 29th 8.8 35.8 v low 25%
Gosnells City 26.7 +0.2 39.5 11th 14.4 -0.4 10.0 20th 8.0 41.7 low 19%
Jandakot Aero 26.2 +0.4 39.2 11th 13.5 +1.0 6.2 3rd 16.4 41.1 low 40%
Karnet 24.3 +1.0 36.6 11th 12.6 +0.8 6.2 29th 19.1 64.6 low 30%
Mandurah 24.5 +0.4 33.2 10th 16.9 +1.1 10.3 29th 8.2 37.5 low 22%
Millendon (Swan Valley) 27.5   40.4 11th 13.2   7.1 29th 10.2
Pearce RAAF 28.0 +1.5 40.7 11th 13.5 +0.2 7.0 3rd 10.4 34.0 low 31%
Perth Airport 26.9 +1.3 39.6 11th 13.5 +0.5 8.3 3rd 14.0 39.7 low 35%
Perth Metro 26.4 +0.5 39.5 11th 14.7 +0.9 8.9 3rd 13.2 35.2 low 38%
Rottnest Island 24.2 +0.5 35.2 11th 17.9 +0.6 12.5 29th 6.6 32.3 low 20%
Swanbourne 25.2 -0.1 37.3 11th 16.3 +1.0 10.8 29th 14.0 38.3 low 37%

Daily maximum temperatures for April 2020
123456789101112131415161718192021222324252627282930
Bickley26.122.422.222.121.828.531.131.533.233.836.524.524.023.221.022.925.320.819.220.321.521.122.819.821.024.123.019.018.718.3
Garden Island HSF23.722.220.624.225.031.834.429.128.126.537.125.625.722.422.621.023.321.321.923.324.523.123.223.121.722.720.419.022.122.2
Gosnells City24.524.526.225.532.534.533.536.639.526.626.525.525.026.128.221.523.024.525.025.025.423.224.426.423.521.622.8
Jandakot Aero27.424.523.825.324.731.834.832.733.535.139.226.126.025.024.124.426.921.122.024.024.524.924.922.623.626.022.620.721.921.6
Karnet26.122.422.321.021.131.732.032.034.536.624.524.522.622.023.026.822.519.120.821.520.523.221.021.424.221.118.3
Mandurah24.623.321.624.824.431.330.226.829.133.230.425.725.824.223.722.425.521.522.023.023.222.323.723.722.623.521.120.021.421.1
Millendon (Swan Valley)29.725.925.326.027.632.935.035.436.338.040.427.127.326.024.826.128.522.822.924.725.825.525.623.424.127.224.921.822.022.0
Pearce RAAF30.126.725.525.828.132.535.735.837.739.240.727.728.026.325.626.529.423.923.825.026.225.526.323.624.527.726.322.122.221.8
Perth Airport28.525.225.325.026.332.035.034.435.335.839.626.426.625.625.125.928.521.922.824.325.524.325.522.824.226.524.021.722.121.6
Perth Metro27.124.123.724.626.531.833.632.634.035.639.526.226.724.924.225.127.422.122.724.424.524.625.122.823.826.423.620.821.821.4
Rottnest Island23.223.720.523.425.130.130.527.230.027.235.225.525.024.023.421.123.421.722.023.523.424.422.623.422.722.021.619.520.420.4
Swanbourne24.024.121.824.926.032.135.230.329.631.537.324.825.124.023.723.025.421.422.123.924.124.323.022.823.023.421.220.321.721.4
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 April 2020
123456789101112131415161718192021222324252627282930
Bickley12.615.28.58.911.513.615.419.318.618.517.519.415.013.713.011.413.015.314.610.313.813.914.513.614.811.212.911.56.66.9
Garden Island HSF16.918.913.314.116.617.021.217.617.019.018.420.621.117.319.514.616.015.217.817.818.520.518.915.118.614.316.216.011.312.0
Gosnells City14.311.013.616.820.116.521.516.114.013.813.015.513.114.310.016.015.015.017.012.511.613.011.010.7
Jandakot Aero12.117.16.210.514.616.720.616.014.019.920.519.912.912.114.18.912.810.916.89.115.213.712.111.716.110.811.012.97.09.3
Karnet12.815.77.310.013.719.414.719.519.313.110.69.510.814.98.012.512.514.111.215.210.59.810.56.2
Mandurah15.917.912.813.516.617.620.319.418.821.622.022.419.517.219.113.515.416.418.216.016.219.417.415.918.613.815.015.110.311.0
Millendon (Swan Valley)9.917.17.49.516.218.620.515.714.218.420.819.014.711.99.99.112.910.816.38.914.212.412.512.016.110.49.011.07.110.4
Pearce RAAF8.717.07.09.816.619.322.415.415.317.620.519.015.310.811.28.414.210.916.69.613.613.013.112.416.69.88.812.18.111.3
Perth Airport11.017.98.310.015.318.319.415.414.620.221.419.814.011.311.69.412.210.316.39.114.713.413.812.016.410.29.411.49.89.4
Perth Metro13.018.08.911.515.118.519.017.115.719.621.221.715.215.716.310.712.711.917.410.315.113.814.113.716.911.211.214.010.99.4
Rottnest Island17.217.915.014.716.618.621.320.320.121.522.421.619.318.718.315.417.519.017.416.517.518.418.418.218.816.718.116.212.512.8
Swanbourne14.618.611.913.515.718.420.419.418.120.322.421.418.815.618.912.814.814.817.812.116.217.917.515.617.913.213.415.310.810.9
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 April 2020
123456789101112131415161718192021222324252627282930
Anketell - - - - 1.4 - - - - - - - - - - - - - 5.9 0.1 0.5 0.1 0.6 - 0.2 0.6 - 3.4 - -
Bickley - - - - 2.8 - - - - - - - - 0.2 - - - - 10.2 - 2.0 0.2 0.6 - 1.0 1.2 - - - -
Bungendore - - - - 2.0 - - - - - - - - - - - 0.2 - 10.4 0.6 0.6 0.2 1.4 - 3.8 0.4 0.2 0.4 - -
Chidlow - - - - - 1.1 - - - - - - - - - - - - - 9.5 0.5 - 0.1 - 1.2 0.6

Garden Island HSF - - 0.6 0.2 0.4 0.2 - 0.4 0.6 - - -
- - - - - 4.4 0.6 0.6 0.2 0.2 - - 0.2 - 0.2 - -
Gidgegannup - - - - 0.8 - - - - - - - - - - - - - 8.8 - 0.4 - 0.6 - 6.6 0.2 - 0.4 - -
Gosnells City - - - - - - - - - - - - - - - - - - 5.0 - - - 1.0 2.0 - - - - -
Huntly - - - - 1.1 - - - - - - - 1.0 - - - - - 7.8 0.2 0.2 0.5 2.8 - - 0.5 - 1.5 - -
Jandakot Aero - - - - 1.6 - - - - - - - - - - - - - 10.2 0.2 - - 1.0 - 0.8 1.0 - 1.6 - -
Jarrahdale - - - - 0.8 - - - - - - - 0.4 - 0.2 - - 0.2 13.4 0.8 2.6 0.4 2.8 - 2.2 0.2 0.4 0.4 0.2 -
Karnet - - - - 1.0 0.2 - - - - - 0.3 0.5 - - - - - 9.2 0.2 2.5 0.2 3.6 - 0.5 - - 0.9 -
Karragullen North - - - - 2.8 - - - - - - - - - - - - - 7.6 - 1.2 - 1.0 - 0.6 - - 1.0

Maida Vale - - - 1.2 - - - - - - - - - - - - - - 6.8 - 1.2 - 2.0 - 1.6 9.4 - 1.0

Mandurah - - - - - 0.2 - - - - - - - - - - - - 3.2 - - 0.8 1.0 0.2 2.6 - 0.2 - - -
Millendon (Swan Valley) - - - - 0.8 - - - - - - - - - - - - - 5.6 0.6 0.4 - 0.4 0.2 1.0 1.0 - 0.2 - -
Mount Solus 0.2 - - - 0.6 0.2 - - - - - - - 0.4 - - - - 9.0 0.2 1.4 0.2 4.2 - 0.4 0.2 - 0.2 - -
Muchea - - - - 1.8 0.2 - - - - - - - - - - - - 5.8 - 0.2 - 0.4 - - 0.6 0.2 - - -
Mundaring - - - - 1.8 - - - - - - - - - - - - - 12.2 0.2 1.2 0.4 - 2.0 2.4 - 0.4

Pearce RAAF - - - - 0.4 0.2 - - - - - - - - - - - - 6.0 0.8 0.4 0.2 - - 1.2 1.0 - 0.2 - -
Perth Airport - - - - 1.4 - - - - - - - - - - - - - 6.6 0.2 0.6 - 1.2 - 2.8 1.2 - - - -
Perth Metro - 0.2 - - 1.4 - - - - - - - - - - - - - 6.4 - 0.4 0.2 1.0 - 2.6 0.2 - 0.8 - -
Pinjarra South - - - - 0.2 - - - - - - - - - - - - - 3.8 0.2 - 0.4 0.2 - 0.8 - - 0.4 - -
Roleystone - - - - 3.2 - - - - - - - - - - - - - 8.2 - 2.8 0.2 1.0 - 1.6 - - 1.8

Rottnest Island - - - - 0.4 - - - 0.2 - - - - - - - - - 4.2 0.2 0.2 0.6 - - - 0.2 - 0.4 0.2 -
Serpentine - - - - 0.2 0.2 0.6 - - - - - - - - - - - 10.6 0.4 1.6 0.2 1.6 0.2 1.0 0.2 - - 0.2 -
Subiaco Treatment Plant - - 0.4


























Swanbourne - - - - 1.8 - - - - - - - - - - - - - 5.2 - 0.2 - 0.2 - 5.6 0.2 - 0.8 - -
Tamala Park (Mindarie) - - 2.8 - - - - - - - - - - - - - - - 4.0 0.1 0.4 - 0.1 - 0.1 0.4 - 1.0 - -
Wanneroo - - - 2.2 - - - - - - - - - - - 7.4 - - 1.2 - - 1.6
Werribee - - - - 1.4 - - - - - - - - - - - - - 4.4 0.2 - - - 0.2 3.0 - 0.2 0.4 0.2 -
Whiteman Park - - - - 0.4 - - - - - - - - - - - - - 7.2 0.8 2.0 - 3.2 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 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 9 am on Friday 1 May 2020. 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