Greater Perth in August 2017: A wet month

Rainfall in August 2017 was above average for the Greater Perth area, with totals generally between 120 mm and 170 mm, and higher in the hills. Mean maximum temperatures were generally close to normal, while mean minimum temperatures were mostly above average.

This summary includes data from observing sites in or near the Greater Perth “Greater Capital City Statistical Area” (GCCSA) – see the notes.

Above average rainfall

  • Rainfall was mostly in the 120 mm to 170 mm range on the islands and the coastal plain, and in the 220 mm to 270 mm range in the hills
  • A number of sites in southern Greater Perth had their wettest August in 25 years
  • Rain days were generally between 18 and 20; a wet period between the 8th and 20th saw most sites record rainfall on every day
  • Wettest day was the 9th with most sites reporting between 40 mm and 60 mm; Rottnest Island registered its wettest August day in 23 years

Near normal mean maximum temperatures; above average mean minimum temperatures

  • Mean maximum temperatures were generally close to normal, and within 0.5 °C of the average
  • Days were mostly cool for the first three weeks of August, but temperatures were mild in the low to mid-twenties in the last week of August
  • Mean minimum temperatures were mostly 0.5 °C to 1.5 °C above average
  • A very cold start to August in terms of overnight temperatures, though nights were mostly cool to mild for the remainder of August

Perth Metro

  • Total rainfall was 151.6 mm, its wettest August for four years, since 167.4 mm was recorded in August 2013
  • Rain days totalled 18, which was above the August average of 15.8 rain days
  • Mean maximum temperature was 18.7 °C, 0.4 °C below average
  • A daily maximum temperature of 14.2 °C on the 9th was Perth Metro's coldest August day for 13 years, since 28 August 2004 when 13.3 °C was recorded
  • Mean daily minimum temperature was 9.4 °C, which was 1.0 °C above average and the highest in August for three years, since 2014 when a minimum of 10.3 °C was recorded
  • A daily minimum of 1.7 °C on the 2nd was the lowest temperature for 12 months, since 1.6  °C was recorded on 1 August 2016

Further information

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Extremes in August 2017
Hottest day 25.7 °C at Mandurah on the 27th
Warmest days on average 19.2 °C at Medina Research Centre
Coolest days on average 15.4 °C at Bickley
Coldest day 10.2 °C at Karnet on the 9th
Coldest night 0.7 °C at Jandakot Aero on the 2nd
Coolest nights on average 7.8 °C at Bickley
Warmest nights on average 12.3 °C at Rottnest Island
11.4 °C at Mandurah
Warmest night 15.7 °C at Rottnest Island on the 8th
15.1 °C at Rottnest Island on the 7th
15.1 °C at Perth Metro on the 14th
15.1 °C at Swanbourne on the 14th
15.1 °C at Rottnest Island on the 30th
Warmest on average overall 15.1 °C at Rottnest Island
14.7 °C at Garden Island HSF
14.7 °C at Mandurah
Coolest on average overall 11.6 °C at Bickley
Wettest overall 278.2 mm at Huntly
Driest overall 113.2 mm at Rottnest Island
Wettest day 71.0 mm at Huntly on the 9th
Strongest wind gust 94 km/h at Ocean Reef on the 9th



Highest August total rainfall for at least 20 years
Observed
(mm)
Most recent
higher
Average for
August
Medina Research Centre 169.2 170.7 in 1992 115.4
Jarrahdale 258.0 277.2 in 1992* 183.8
Pinjarra Refinery 179.7 192.0 in 1992* 125.7

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



Summary statistics for August 2017
Maximum temperatures
(°C)
Minimum temperatures
(°C)
Rainfall
(millimetres)
Mean for
August
2017
Diff
from
average
Highest for
August
2017
Mean for
August
2017
Diff
from
average
Lowest for
August
2017
Total for
August
2017
Average
for
August
Rank of
August
2017
Fraction of
August
average
Bickley 15.4 -0.6 22.0 28th 7.8 +0.2 3.4 1st 224.2 173.5 high 129%
Garden Island HSF 17.8 -0.4 24.4 27th 11.7 +0.4 4.8 3rd 132.6 94.9 v high 140%
Gosnells City 18.9 -0.5 25.1 28th 10.2 +1.3 3.4 1st 143.5 126.4 average 114%
Jandakot Aero 18.4 -0.3 25.2 28th 9.0 +1.9 0.7 2nd 169.0 127.5 high 133%
Mandurah 18.1 0.0 25.7 27th 11.4 +0.4 5.7 2nd 129.2 95.4 high 135%
Medina Research Centre 19.2 +0.3 24.9 27th 9.1 +0.9 1.2 2nd 169.2 115.4 v high 147%
Millendon (Swan Valley) 18.8   23.7 28th 8.5   1.4 2nd 153.6
Pearce RAAF 18.7 +0.3 23.9 28th 8.8 +0.6 2.0 2nd 126.0 104.8 high 120%
Perth Airport 18.8 +0.2 24.6 28th 9.1 +1.1 1.0 2nd 144.6 118.1 high 122%
Perth Metro 18.7 -0.4 24.4 28th 9.4 +1.1 1.7 2nd 151.6 132.9 high 114%
Rottnest Island 17.9 0.0 22.8 27th 12.3 -0.1 8.2 1st 113.2 87.1 high 130%
Swanbourne 18.3 -0.6 24.4 27th 10.8 +0.7 5.1 2nd 156.2 117.8 v high 133%
Note: Observations for “Perth Metro” are taken from the current site at Mount Lawley (Bureau number 009225).
Comparisons are made against combined data from the current site (which opened in early 1993) and the previous site at Perth Regional Office (009034), which ran from 1876 to early 1992.

Daily maximum temperatures for August 2017
12345678910111213141516171819202122232425262728293031
Bickley12.112.413.611.715.116.715.715.210.312.815.315.816.513.713.713.114.817.514.413.413.216.616.818.920.518.020.822.015.617.215.1
Garden Island HSF14.216.517.616.217.919.018.319.114.216.217.319.119.717.216.415.816.818.616.415.315.617.617.520.916.920.524.421.318.119.017.7
Gosnells City15.215.218.016.020.519.518.414.516.318.319.821.020.017.516.918.521.018.017.017.519.722.422.121.024.125.117.8
Jandakot Aero15.414.518.215.418.019.218.818.014.315.917.419.520.417.716.916.517.619.517.416.616.318.919.622.020.720.524.325.217.619.618.7
Karnet12.013.016.316.315.610.213.016.017.014.413.614.013.616.016.321.222.118.0
Mandurah14.716.016.515.818.118.217.918.114.316.016.818.118.417.116.815.415.716.717.416.816.118.619.221.419.921.625.725.620.119.317.9
Medina Research Centre15.914.919.017.020.019.818.719.414.817.218.020.020.518.817.019.219.518.517.418.018.719.722.221.022.024.924.120.419.7
Millendon (Swan Valley)14.915.418.315.218.919.518.119.414.316.318.520.020.117.817.116.818.020.117.817.317.319.719.421.622.120.423.323.720.820.319.1
Pearce RAAF14.815.718.315.019.319.318.919.314.316.219.219.020.317.816.816.117.920.317.616.718.019.119.221.321.819.623.823.921.520.119.2
Perth Airport15.314.917.915.518.319.819.419.214.716.118.119.920.718.017.316.818.220.517.216.917.619.219.722.021.821.223.824.618.619.818.3
Perth Metro15.114.818.515.718.619.718.818.414.216.718.320.220.318.417.416.618.220.718.016.917.018.519.322.321.020.824.224.418.520.118.8
Rottnest Island14.614.818.116.118.219.319.120.214.616.317.619.419.417.416.816.617.918.917.316.017.517.717.319.417.319.422.819.717.819.617.9
Swanbourne15.214.218.116.218.719.318.118.214.616.818.219.420.017.917.116.617.120.117.917.015.918.219.322.118.220.724.423.417.519.818.5
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 August 2017
12345678910111213141516171819202122232425262728293031
Bickley3.43.54.05.67.87.69.711.26.24.16.310.811.612.07.58.24.96.68.08.16.98.28.76.77.38.39.69.011.010.89.6
Garden Island HSF8.77.54.810.512.011.014.214.59.99.911.114.215.415.012.312.99.911.311.011.711.710.910.711.011.612.313.613.011.913.214.5
Gosnells City3.43.64.58.510.97.611.813.89.16.59.813.813.914.011.010.95.79.610.59.07.511.010.811.211.713.914.014.412.7
Jandakot Aero2.00.72.78.110.56.410.312.98.65.38.913.614.314.711.111.65.08.110.29.38.010.67.07.59.37.613.111.410.310.39.8
Karnet4.92.05.69.511.46.63.06.112.011.68.48.27.47.05.67.47.010.29.19.7
Mandurah7.35.78.310.112.112.114.214.39.98.09.913.114.614.212.012.18.310.010.211.411.811.210.610.210.412.413.212.712.914.214.6
Medina Research Centre3.21.22.78.311.09.09.713.08.35.69.413.514.014.411.25.39.710.09.510.611.07.47.98.09.511.011.79.49.49.2
Millendon (Swan Valley)2.31.42.77.68.75.78.210.68.35.46.313.112.913.610.69.34.17.49.78.75.27.86.98.48.410.211.612.912.411.710.0
Pearce RAAF2.72.03.67.89.95.68.611.98.65.86.313.213.113.710.09.95.67.59.99.05.57.86.39.710.78.612.513.213.211.210.3
Perth Airport1.81.03.67.99.36.710.612.58.55.37.513.213.114.611.410.85.07.09.79.25.89.910.39.38.910.212.212.811.012.010.1
Perth Metro4.21.74.48.611.07.410.013.38.96.18.913.614.215.111.611.76.58.910.010.36.69.88.58.17.59.312.212.611.010.59.9
Rottnest Island8.28.99.810.212.613.615.115.79.79.912.013.514.614.09.911.411.212.111.412.312.912.411.711.712.913.313.813.814.315.114.0
Swanbourne6.45.16.39.211.49.113.614.39.07.410.114.114.315.111.912.07.39.210.111.010.211.09.99.89.611.113.012.813.112.813.9
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 August 2017
12345678910111213141516171819202122232425262728293031
Anketell 29.2 - - 4.8 0.4 - - 2.0 61.2 12.2 0.6 20.8 7.8 11.8 9.4 3.4 1.8 2.2 9.2 4.8 - - - - - - - - - 0.6 1.6
Bickley 32.2 - 0.6 6.8 0.8 - - 0.4 55.4 12.8 - 30.2 7.4 24.8 31.8 4.8 0.6 - 9.2 0.6 - 0.4 0.2 - - - - - - 1.6 3.6
Bungendore 29.0 0.2 1.2 6.4 0.2 - - 1.6 46.2 10.4 0.2 29.2 6.0 12.2 14.0 4.2 2.2 1.4 8.2 1.6 - 0.4 0.2 - - - 0.2 - - 1.0 2.6
Chidlow 25.8 - - 1.8 0.4 - - - 40.4 10.2 - 21.6 24.6 16.8 4.6 - - 5.0 4.2 - - - - - - - 0.4 0.4 5.2
Garden Island HSF 21.0 - 0.4 2.0 - - 0.2 4.4 42.0 4.2 - 18.0 1.2 8.4 3.4 3.6 7.2 3.4 6.4 3.4 0.4 0.2 - - - - - - - - 2.8
Gosnells City 22.4 0.2 0.6 5.0 0.4 - - 0.6 41.8 8.6 0.2 5.0 7.0 4.6 0.8 0.4 - - - - - - - - - - - 13.4
Halls Head 16.2 - - - - - 7.0 9.0 30.0 6.0 3.1 11.4 8.4 9.4 4.0 3.0 3.0 5.6 9.4 0.8 0.6









Huntly 49.0 - 1.3 9.6 0.1 0.2 1.2 12.0 71.0 10.2 1.8 26.0 19.4 30.4 17.8 5.2 3.2 8.0 5.7 0.3 - 0.4 0.2 - - - - - - - 5.2
Jandakot Aero 22.0
1.2 5.2 1.0 - - 4.6 50.6 9.0 - 23.0 6.4 9.8 10.0 3.4 0.8 1.0 8.0 2.2 - 0.6 - - - - - - - 5.0 5.2
Jarrahdale 34.8 0.2 1.8 6.8 0.2 - 0.2 3.6 59.2 11.8 1.0 44.6 22.8 20.6 15.4 3.8 3.2 1.6 9.2 6.8 - 0.2 0.2 0.4 - - 0.2 0.2 - 0.4 8.8
Karnet 32.4
2.4 7.8 0.3 6.4 39.4 8.0 - 22.6 34.0 8.2 4.8 2.4 - 0.3 - - - - - - - 0.3
Karragullen North 33.4 - - 7.4 0.3 - - 1.6 49.0 14.2 - 30.2 13.0 12.6 13.8 10.0 0.4 - 8.4 1.6 - 0.4 - - - - - - - 2.0 3.6
Maida Vale 20.8 0.4 0.8 4.8 1.0 - - 0.4 46.2 6.4 - 20.8 5.4 12.8 11.2 7.6 2.2 - 11.4 0.4 - 0.4 - - - - - - - 0.2 1.8
Mandurah 14.8 - 1.0 1.8 - - - 13.4 38.4 4.6 0.6 7.2 6.6 10.8 4.0 3.0 3.0 6.6 9.4 0.8 0.6 1.0 - - - - - - - - 1.6
Medina Research Centre 24.8 - 1.0 2.8 0.6 0.1 0.2 4.4 49.8 8.6 3.0 16.8 12.8 11.2 5.8 7.4 0.6 14.0 1.6 0.2 - - - - - - - 0.1 0.4 3.0
Midland 24.2 0.2 0.2 - 1.2 - 49.4 10.8 - 51.2 10.0 4.4 - - 4.6 - - - - - - - - 2.2 6.2
Millendon (Swan Valley) 30.6 - 0.2 2.4 0.4 0.2 - - 41.0 11.6 - 17.6 6.8 17.0 12.4 6.0 0.4 - 5.6 0.4 - - - - - - - - - 0.6 0.4
Mount Helena 35.7
0.4 3.2 0.4


49.0 11.4
24.0 6.4 17.0 22.6 4.2 0.4
5.4 1.4









3.0
Mount Solus 27.2 0.2 1.2 1.8 - 0.2 - 3.6 43.6 10.6 0.6 41.4 21.0 26.4 16.6 5.2 2.0 1.0 7.8 0.4 - 0.4 0.2 - 0.2 - - 0.2 - 0.2 4.2
Muchea 20.6 0.2 - 1.6 - - - - 57.4 6.4 0.2 17.2 9.8 14.2 11.8 6.8 0.8 - 4.2 0.8 - 0.6 - - - - - - - 0.2 1.6
Mundaring 34.8 - 0.6 5.8 0.6 0.2 - - 57.8 10.2 - 28.4 21.0 24.8 22.2 5.0 4.0 - 5.4 3.8 - 0.4 - - - - - - 0.2 0.2 3.0
Noble Falls 29.0
0.8 3.0 0.8


42.0 12.6
21.0 10.0 22.0 18.0 4.0 0.4
5.8 0.4
0.2






1.0 1.4
Pearce RAAF 26.4 - - 1.8 - - - - 40.0 4.0 0.2 13.4 4.2 12.0 9.2 6.4 0.2 - 7.8 - - 0.2 - - - - - - - - 0.2
Perth Airport 23.6 - - 1.8 0.2 - - 0.2 41.4 6.4 0.2 19.8 5.6 10.2 11.8 5.2 1.2 0.2 10.0 1.6 0.2 0.8 - - - - - - - - 4.2
Perth Metro 27.4 - 0.4 2.6 0.8 - - 0.2 47.2 9.2 - 19.8 2.2 6.6 8.4 5.4 1.0 - 11.0 2.8 - 0.6 - - - - - - - 1.4 4.6
Pickering Brook 33.8
0.4 6.0 1.2

0.8 47.4 13.6
24.6 10.0 11.4 17.5 8.0 0.4
8.2 1.4
0.6






3.6 5.8
Pinjarra Refinery 18.2 0.1 1.0 5.6 - - 0.4 20.0 42.2 11.0 1.0 15.0 14.2 14.0 8.6 3.8 3.8 12.2 5.8 0.3 0.2 - - - - - - - - - 2.3
Pinjarra South 22.6 - 0.8 3.6 - - 0.4 14.8 33.0 7.4 0.6 11.4 12.2 7.6 7.4 4.0 3.0 8.4 5.2 - - - - - - - - - - - 2.6
Roleystone 26.8 - 0.8 7.8 - - - 1.6 42.4 13.4 - 23.2 13.4 10.8 17.8 9.8 0.8 - 8.6 1.4 - 0.8 - - - - - - - 5.4 3.4
Rottnest Island 17.0 - 2.2 3.0 - - - 5.6 34.6 1.6 0.6 10.6 1.0 8.2 2.4 4.6 1.6 2.6 9.6 0.6 - 1.6 1.8 - - - - - 0.2 0.2 3.6
Serpentine 27.6 - 0.8 5.0 - - - 2.0 48.2 9.4 0.2 38.6 19.4 11.2 8.6 2.8 3.4 1.2 10.4 0.8 - - - - - - - - - - 5.0
Swanbourne 22.0 - 2.8 3.0 0.2 - - 1.6 46.4 7.8 0.2 19.2 3.0 6.6 4.0 3.8 4.6 2.0 16.4 0.2 - 1.4 - - - - - - - 9.2 1.8
Wanneroo 24.5 - - - 0.8 0.4 40.6 2.4 - 44.4 6.0 6.0 2.0 - 20.0 1.4 - - - - - - 0.3 0.2 1.6
Whiteman Park 29.2 - 0.8 5.2 - - - - 49.8 12.0 - 25.6 7.6 14.2 14.4 5.6 - - - - - 7.4 - - - - - - - 4.4 4.4
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.

In September 2017 this summary was broadened to include 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 September 2017. 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
Enquiries