Greater Perth in July 2020: dry and warm

July 2020 was a dry and warm month across Greater Perth. Monthly rainfall was well below the July average. Both mean maximum and minimum temperatures were warmer than average.

Below average rainfall

  • July monthly rainfall varied from 60–90 mm in the coastal plain sites, up to 130–190 mm in the Perth hills.
  • Most sites had 15 or 16 rain days; wettest days were the 14th and 17th with widespread daily rainfall in excess of 10 mm; the highest daily rainfall of the month was 41.6 mm at Karnet on the 17th
  • Perth Metro recorded a monthly rainfall of 83.4 mm, which was its fourth-driest July on record and driest July since 2012, with rainfall records commenced in 1993.

Warmer than average days and nights

  • Mean maximum and minimum temperatures were 0.5 °C to 1.5 °C above average across Greater Perth.
  • Jandakot Airport and Bickley had their highest July mean daily maximum temperature on record
  • Perth Metro's mean maximum temperature 19.4 °C was its equal second-highest in July on record, equalling with July 2012; the record is 19.5 °C set in July 2007 with recorded commenced in 1993.
  • The warmest days with temperatures at 20 °C or above across Greater Perth were on the 5th, 22nd and 27th; Perth Airport recorded the highest temperature of the month at 25.1 °C on the 27th.
  • A handful of cold nights with minimum temperatures at 5 °C or lower were observed during the month, with the lowest temperature 3.1 °C at Karnet on the 10th and at Pearce RAAF on the 24th.
  • The mildest night with minimum temperatures in the low-to-mid 10s across Greater Perth was on the 27th; Swanbourne had its warmest July night on record.

Perth Metro

  • Total rainfall for Perth Metro was 83.4 mm, which is 59% of the long-term average of 142.3 mm
  • The mean daily maximum temperature for Perth Metro was 19.4 °C, which is 1.0 °C above the long-term average of 18.4 °C
  • The warmest day was 24.4 °C on the 27th, and the coolest day was on the 17th when the temperature reached 15.0 °C
  • The mean daily minimum temperature for Perth Metro was 9.1 °C, which is 1.2 °C above the long-term average of 7.9 °C
  • The coldest morning was 4.3 °C on the 2nd, and the warmest morning was on the 23rd when the minimum temperature was 14.5 °C

Further information

Media
(03) 9669 4057

Extremes in July 2020
Hottest day 25.1 °C at Perth Airport on the 27th
Warmest days on average 19.4 °C at Pearce RAAF
19.4 °C at Perth Airport
19.4 °C at Perth Metro
Coolest days on average 16.1 °C at Bickley
Coldest day 11.0 °C at Bickley on the 17th
Coldest night 3.1 °C at Karnet on the 10th
3.1 °C at Pearce RAAF on the 24th
Coolest nights on average 7.1 °C at Karnet
Warmest nights on average 12.9 °C at Rottnest Island
Warmest night 16.8 °C at Rottnest Island on the 27th
Warmest on average overall 15.8 °C at Rottnest Island
Coolest on average overall 11.9 °C at Karnet
Wettest overall 194.2 mm at Huntly
Driest overall 55.0 mm at Rottnest Island
Wettest day 41.6 mm at Karnet on the 17th
Strongest wind gust 89 km/h at Rottnest Island on the 14th


Record highest July mean daily maximum temperature
New record
(°C)
Old
record
Years of
record
Average for
July
Jandakot Aero 19.1 19.0 in 2007 30 18.0
Bickley 16.1 15.9 in 2012 26 15.1



Record highest July daily minimum temperature
New record
(°C)
Old
record
Years of
record
Average for
July
Swanbourne 16.0 on the 27th 15.8 on the 16th in 2017 27 9.7



Summary statistics for July 2020
Maximum temperatures
(°C)
Minimum temperatures
(°C)
Rainfall
(millimetres)
Mean for
July
2020
Diff
from
average
Highest for
July
2020
Mean for
July
2020
Diff
from
average
Lowest for
July
2020
Total for
July
2020
Average
for
July
Rank of
July
2020
Fraction of
July
average
Bickley 16.1 +1.0 21.5 27th 7.9 +0.7 4.1 11th 132.2 215.1 low 61%
Garden Island HSF 18.6 +0.8 22.5 27th 12.0 +0.8 8.2 10th
Jandakot Aero 19.1 +1.1 24.0 27th 8.3 +1.4 3.3 25th 107.0 171.7 low 62%
Karnet 16.6 +1.1 21.6 5th 7.1 +0.8 3.1 10th 182.8 217.0 low 84%
Mandurah 18.1 +0.6 20.5 26th 11.2 +0.5 6.9 11th 85.6 115.2 low 74%
Millendon (Swan Valley) 19.3   24.6 27th 8.6   3.3 24th 59.4
Pearce RAAF 19.4 +1.5 24.9 27th 9.2 +0.8 3.1 24th 68.2 132.8 v low 51%
Perth Airport 19.4 +1.4 25.1 27th 8.6 +0.6 3.6 2nd 70.0 154.2 v low 45%
Perth Metro 19.4 +1.0 24.4 27th 9.1 +1.2 4.3 2nd 83.4 142.3 low 59%
Rottnest Island 18.6 +0.8 22.5 27th 12.9 +0.5 8.9 18th 55.0 111.0 v low 50%
Swanbourne 19.1 +0.7 23.5 5th 10.9 +1.2 6.2 10th 75.2 147.0 v low 51%

Daily maximum temperatures for July 2020
12345678910111213141516171819202122232425262728293031
Bickley13.714.916.518.620.215.314.914.514.612.714.118.815.514.013.717.211.014.212.015.716.920.215.215.618.917.721.516.817.718.517.7
Garden Island HSF15.616.719.621.722.018.418.016.515.715.817.620.319.217.216.718.914.917.616.518.919.421.418.018.520.922.122.519.320.019.517.7
Gosnells City16.818.715.218.720.423.220.2
Jandakot Aero15.717.419.522.523.119.717.916.316.615.717.421.619.517.317.619.914.817.916.018.720.522.718.919.322.021.224.019.620.020.119.6
Karnet14.015.417.420.521.615.915.014.614.913.815.619.315.714.014.815.512.214.713.216.917.820.615.017.519.118.221.316.518.818.017.1
Mandurah15.816.719.219.720.217.817.516.515.815.617.218.718.817.017.818.614.517.116.818.918.819.318.118.019.520.520.019.520.119.718.5
Millendon (Swan Valley)16.817.919.422.122.919.117.517.317.016.117.820.919.317.818.220.114.618.516.018.521.423.519.418.522.321.024.619.120.721.019.7
Pearce RAAF16.317.219.422.223.719.517.618.016.815.617.421.720.317.417.820.415.317.715.018.721.423.519.018.522.921.324.919.421.221.119.4
Perth Airport16.517.919.722.323.319.718.117.417.515.917.521.418.917.617.620.415.317.615.718.820.823.919.619.022.421.125.119.521.121.220.1
Perth Metro16.317.819.522.323.119.418.017.117.116.217.522.319.218.017.720.215.018.315.418.620.623.519.218.922.420.824.419.321.021.119.8
Rottnest Island15.916.118.621.321.418.417.717.215.214.416.220.919.516.819.319.716.018.115.618.419.621.418.718.921.121.122.519.019.719.718.2
Swanbourne16.417.719.722.423.519.018.017.415.915.717.722.219.417.216.819.914.817.015.619.021.621.618.619.722.621.122.419.320.019.319.1
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 July 2020
12345678910111213141516171819202122232425262728293031
Bickley8.75.36.58.09.611.09.38.25.84.24.14.27.88.87.710.28.65.36.05.15.710.111.26.66.911.212.59.38.27.510.2
Garden Island HSF13.19.810.313.613.615.114.312.410.38.28.511.013.511.112.314.111.49.511.39.311.313.715.29.010.213.815.212.712.610.214.7
Gosnells City14.38.57.86.15.63.99.6
Jandakot Aero11.23.76.411.511.312.412.79.24.14.76.54.411.612.28.212.411.16.03.64.45.36.814.54.33.311.113.49.38.85.77.6
Karnet9.26.55.98.39.711.09.56.05.23.14.65.76.79.87.28.57.94.24.84.77.27.34.64.811.511.98.07.45.28.0
Mandurah12.48.29.012.114.115.013.410.68.87.06.98.712.713.211.313.511.39.49.98.510.813.415.18.810.012.914.313.112.09.611.2
Millendon (Swan Valley)11.24.08.112.412.412.310.89.74.25.57.78.88.112.17.112.610.95.53.75.26.08.211.93.34.714.515.410.68.45.46.8
Pearce RAAF11.94.37.912.412.612.49.511.44.25.37.98.09.512.28.113.310.96.95.05.37.79.612.13.18.315.015.411.011.17.07.2
Perth Airport11.23.66.112.913.212.510.59.84.05.35.05.47.212.19.212.511.35.43.64.99.07.513.93.87.414.012.511.09.15.97.9
Perth Metro12.04.37.112.310.412.912.210.76.04.84.87.311.312.49.212.511.67.34.45.15.28.114.54.45.113.914.111.511.66.58.7
Rottnest Island13.111.112.213.516.613.912.213.511.39.910.111.414.610.811.214.111.38.912.211.013.314.715.411.913.515.016.813.915.413.315.3
Swanbourne13.27.18.612.314.113.812.911.47.76.26.28.012.712.810.913.411.38.47.37.59.212.015.97.49.313.616.013.113.19.611.5
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 July 2020
12345678910111213141516171819202122232425262728293031
Anketell 2.2 0.2 - - - 8.1 2.4 5.1 0.2 - - - 6.9 18.8 2.6 3.6 22.3 11.5 0.6 - - - 3.9 0.2 - 8.4 0.2 10.7 0.1 - 0.7
Araluen - - - - 5.4 6.0 4.4 - - - - 5.4 33.0 1.4 1.8 26.4 4.0 0.4 - - - 5.4 2.0 - 8.2 1.0 17.6



Bickley 6.8 0.2 0.2 - - 5.8 10.0 5.6 - 0.4 - - 2.8 39.2 0.6 2.0 20.8 9.6 0.8 - 0.2 - 4.4 0.2 - 2.2 1.2 19.0 0.2 - -
Bungendore 8.4 0.2 - - - 3.0 4.4 4.4 0.2 0.4 - - 4.4 32.2 3.2 2.8 19.2 6.0 0.6 0.2 - - 4.6 0.8 0.2 8.6 - 17.2 - 0.2 0.2
Chidlow 3.3 - - - - 2.8 2.4 3.0 - - - 1.2 23.6 - 0.8 14.4 2.8 0.3 - - - - - 3.8 6.2


Gidgegannup 6.8 0.2 - - - 2.0 4.4 5.8 - 0.4 - - 0.6 25.8 0.8 0.8 20.4 2.6 0.4 - - - 4.0 0.2 - 2.0 0.6 8.2 - - -
Hopelands 2.0 - - - - 11.8 6.0 4.0 - - - - 10.6 17.4 6.4 30.0 1.2 - - - - 5.0 - - 8.8 11.4


Huntly 7.0 - - 0.2 - 12.0 26.8 7.8 - - - - 13.8 30.0 5.0 5.0 35.4 3.0 1.0 - - - 11.2 0.6 - 8.8 - 24.0 - - 2.6
Jandakot Aero 4.0
- - - 2.4 4.4 3.8 0.2 0.2
- 6.0 39.2 1.4 4.6 17.2 5.0 1.6 - - - 3.2 - - 2.6 - 11.2 - - -
Jarrahdale 11.4 0.2 0.4 - - 6.0 13.0 7.2 0.2 0.2 0.2 - 7.8 34.0 3.8 4.8 32.6 4.6 1.4 - 0.2 0.4 10.8 0.4 0.2 10.4 0.2 22.6 - 0.2 0.4
Karnet 7.4 - 0.3 - - 4.8 22.3 9.6 0.3 - - - 10.4 27.3 2.0 6.2 41.6 0.2 0.6 0.1 - - 9.8 3.0 - 17.5 - 18.8 0.4 - 0.2
Karragullen North 5.2 0.2 - 8.2 8.8 5.6 0.2 - - - 3.2 40.4 0.6 1.4 25.6 6.6 0.8 - - - 5.0 1.0 - 5.2 0.8 16.2


Maida Vale 4.4 - - - - 3.6 7.2 4.2 - - - - 3.6 23.4 0.4 1.0 14.0 2.0 1.8 - - - 2.2 - - 1.8 1.6 12.0 - - 0.2
Mandurah 2.6 - - - - 16.4 5.4 2.2 - - - - 4.6 4.8 1.0 4.2 21.2 4.0 0.4 - - - 3.4 0.2 - 7.4 0.2 7.2 - - 0.4
Millendon (Swan Valley) 3.4
- - - 2.6 1.2 5.0 - - - - 0.4 12.8 1.6 - 17.4 1.2 0.4 - - - 2.4 0.2 - 1.2 1.6 8.0 - - -
Mount Solus 7.6 - 0.2 - - 4.6 25.8 8.8 - 0.4 0.2 - 10.4 35.2 2.6 6.8 29.8 2.8 0.6 0.2 - - 6.6 0.4 - 5.2 0.2 10.4 - 0.2 -
Muchea 3.6 - 0.2 - - 0.6 2.0 3.0 0.2 - - - 1.6 17.0 1.4 0.2 15.8 1.6 1.6 - 0.2 - 4.2 - - 0.6 4.8 4.8 - - 0.2
Mundaring 10.0 - - 2.6 5.8 7.0 - - 1.0 21.0 1.8 0.8 21.4 3.6 - 1.0 - - 4.4 - - 4.2 - 12.4


Pearce RAAF 7.0
- - - 0.4 0.6 4.6 - 0.2 - - 0.2 20.4 1.8 - 17.0 3.4 2.6 0.2 - - 2.4 - 0.2 0.8 0.8 5.6 -
-
Perth Airport 4.2 0.2 - - - 2.8 3.8 4.0 0.2 0.2 - - 1.6 21.2 0.6 0.4 12.0 3.4 0.4 - - - 1.0 - - 3.6 1.0 9.2 0.2 - -
Perth Metro 3.0
- - - 6.8 6.2 4.6 - - - - 3.4 25.6 1.8 1.0 12.6 1.4 0.4 - - - 1.6 - - 2.2 4.8 8.0 - - -
Pinjarra Refinery 1.6 0.2 - - - 11.2 14.0 3.8 0.1 - - - 15.0 20.6 2.2 2.8 17.0 0.4 0.5 - - - 7.0 0.2 - 4.0 - 12.0 0.2 - 0.6
Pinjarra South 1.6 - - - - 10.4 15.4 3.2 - - - - 8.4 14.0 2.8 3.0 15.8 0.6 1.0 - - - 5.2 - - 2.8 0.2 8.4 - - 0.4
Roleystone 5.6 - - - - 6.2 7.8 - 5.0 - - - 3.0 34.0 2.2 2.6 25.6 6.2 1.4 - - - 5.2 - - 8.2 - 17.0


Rottnest Island 2.0
0.2 - - 7.4 2.0 2.8 4.4 0.2 - - 1.8 4.4 0.4 4.8 12.6 4.2 0.8 - - - 0.2 - - 2.0 0.2 4.4 0.2 - -
Serpentine 5.2 - - - - 3.8 5.4 5.6 0.2 - - - 7.6 21.2 4.0 4.0 31.0 3.0 1.6 - - - 6.0 0.2 - 8.6 - 14.0 - - 0.4
Subiaco Treatment Plant 2.2 - - - - 3.2 8.8 4.8 - - - - 1.2 22.2 1.4 6.8 9.6













Swanbourne 2.2
- - - 2.0 5.8 3.6 - 0.2 - - 1.4 23.0 1.2 7.2 12.0 1.8 1.8 - - - 1.4 - - 3.0 0.4 7.6 - - 0.6
Tamala Park (Mindarie) 3.1 - - - - 2.8 0.5 6.9 2.0 - - - 0.8 17.6 5.4 1.8 18.2 1.0 2.6 - - - 0.5 - - 0.4 2.0 4.6 0.1

Wanneroo 3.8 - - 8.8 5.2 4.4 - 1.2 29.8 0.6 1.4 18.6 - - - 5.8 - 1.8 - 2.0 7.4 - - 0.6
Werribee 4.2 0.2 - - - 0.2 1.2 5.2 0.2 - 0.2 - 1.2 20.8 1.0 - 15.6 4.2 0.2 - - - 4.0 0.2 - 1.8 0.2 4.2 - 0.2 -
Whiteman Park 3.0 0.2 - 3.2 2.4 6.8 - - 1.8 23.8 1.6 0.4 15.2 1.4 - - - - 3.0







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 11 am on Monday 3 August 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