Perth in August 2015: A near average month

Rainfall in August 2015 was near the long-term average for most Perth sites, and day-time and overnight temperatures were also generally near the long-term average.

  • Near average rainfall for most sites
  • Lowest August day-time temperatures for five years at Perth Metro
  • Lowest August overnight temperatures for three years at Perth Metro

Rainfall in August was near average across the Perth metropolitan area. Most of the rainfall was recorded during four periods: on the 1st, from the 7th to 11th, from the 17th to 22nd, and from the 29th to 30th, as cut-off lows and cold fronts impacted the region. Perth Metro recorded a total of 113.0 mm on 15 rain days, which is about 15 percent below the long-term average of 133.1 mm for the Perth official site (rainfall records commencing in 1876).

Mean maximum temperatures were near the long-term average for most sites, ranging from the mid-teens in the hills to the high teens in the remainder of the metropolitan area. Perth Metro recorded a mean maximum temperature of 19.3 °C in August, which is close to the long-term average, but the lowest in August for five years, since 2010 when a mean maximum temperature of 19.1 °C was recorded. Days were mainly cool, with daily maxima in the mid-to-high teens, whilst mild to warm days with daily maximum temperatures in the low to mid-twenties were observed between the 14th and 17th, and between the 26th and 29th. Several sites registered their warmest or equal warmest August day on record on the 15th as temperatures reached the mid-to-high twenties. The highest maximum temperature of the month for the metropolitan area was recorded at both Median Research Centre and Swanbourne on the 15th with 28.0 °C. Perth Metro's lowest maximum temperature in August 2015 was 15.2 °C on the 8th, which continued a run of daily maxima at or above 15.0 °C for 25 months, since July 2013. This exceeded the previous longest such run of 24 months recorded between August 1987 and June 1989.

Mean minimum temperatures were near average for most sites in Perth during August 2015. Perth Metro recorded a mean minimum temperature of 9.1 °C, which is near the long-term average, but the lowest mean minimum for August at the site for three years, since 2012 when a mean minimum temperature of 8.6 °C was recorded. Very cold nights with minima at 5 °C or below were observed on the 2nd and 3rd, the 9th, and the 22nd for coastal plain sites. Cool nights with minima at 10 °C or above were mostly observed during the second half the month, from the 17th to 20th, and from 28th to 30th. Most sites recorded their mildest night of the month on the 17th, with minima in the mid-teens.

 

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Extremes in August 2015
Hottest day 28.0 °C at Medina Research Centre on the 15th
28.0 °C at Swanbourne on the 15th
Warmest days on average 19.8 °C at Swanbourne
Coolest days on average 16.1 °C at Bickley
Coldest day 10.9 °C at Bickley on the 8th
Coldest night -0.5 °C at Karnet on the 9th
Coolest nights on average 7.2 °C at Karnet
Warmest nights on average 12.5 °C at Rottnest Island
10.5 °C at Swanbourne
Warmest night 16.3 °C at Rottnest Island on the 28th
15.6 °C at Pearce RAAF on the 17th
Warmest on average overall 15.5 °C at Rottnest Island
15.1 °C at Swanbourne
Coolest on average overall 11.9 °C at Karnet
Wettest overall 185.0 mm at Karnet
Wettest day 39.6 mm at Bickley on the 20th
Strongest wind gust 89 km/h at Rottnest Island on the 8th

Record highest August temperature
New record
(°C)
Old
record
Years of
record
Average for
August
Karnet 25.0 on the 15th = 25.0 on the 26th in 1998 50 16.0
Medina Research Centre 28.0 on the 15th 26.2 on the 17th in 2014 30 18.9
Jandakot Aero 27.0 on the 15th = 27.0 on the 26th in 1998 26 18.7
Rottnest Island 25.3 on the 15th 23.3 on the 17th in 2014 26 17.9
Swanbourne 28.0 on the 15th 26.2 on the 6th in 2014 22 18.9



Summary statistics for August 2015
Maximum temperatures
(°C)
Minimum temperatures
(°C)
Rainfall
(millimetres)
Mean for
August
2015
Diff
from
average
Highest for
August
2015
Mean for
August
2015
Diff
from
average
Lowest for
August
2015
Total for
August
2015
Average
for
August
Rank of
August
2015
Fraction of
August
average
Bickley 16.1 0.0 23.8 15th 7.9 +0.3 2.5 9th 143.6 171.5 average 84%
Garden Island HSF 18.6 +0.4 25.9 15th 11.7 +0.4 5.0 22nd 92.8 90.7 average 102%
Gosnells City 19.4 -0.1 27.8 16th 9.6 +0.6 3.1 9th 123.9 125.8 average 98%
Jandakot Aero 19.2 +0.5 27.0 15th 7.8 +0.7 1.9 9th 131.6 126.1 average 104%
Karnet 16.6 +0.6 25.0 15th 7.2 +0.9 -0.5 9th 185.0 185.9 average 100%
Medina Research Centre 19.5 +0.6 28.0 15th 8.9 +0.7 2.4 9th        
Pearce RAAF 19.3 +0.9 26.8 15th 8.8 +0.6 1.1 3rd 93.4 104.0 average 90%
Perth Airport 19.4 +0.8 27.4 15th 9.2 +1.2 3.3 9th 97.4 117.5 average 83%
Perth Metro 19.3 +0.2 27.0 15th 9.1 +0.8 4.3 3rd 113.0 133.1 average 85%
Rottnest Island 18.5 +0.6 25.3 15th 12.5 +0.1 7.3 9th 104.4 101.8 average 103%
Swanbourne 19.8 +0.9 28.0 15th 10.5 +0.4 5.4 9th 106.0 115.1 low 92%
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.
Observations for “Rottnest Island” are taken from the current site at Rottnest Island (Bureau number 009193).
Comparisons are made against combined data from the current site(which opened in 1995) and the previous site at Rottnest Island Lighthouse (009038),which ran from 1879 to 1994.

Daily maximum temperatures for August 2015
12345678910111213141516171819202122232425262728293031
Bickley13.813.515.015.715.516.914.710.911.414.914.814.814.520.223.820.717.817.316.815.911.714.615.415.816.218.222.118.417.615.613.6
Garden Island HSF16.416.817.318.318.319.018.515.516.818.116.417.515.718.025.922.221.919.319.617.216.616.716.718.619.620.825.520.120.316.917.3
Gosnells City18.117.818.818.418.820.518.515.214.419.017.717.716.327.822.020.621.119.016.017.419.419.519.822.026.021.121.719.218.4
Jandakot Aero17.416.817.817.818.520.118.114.815.719.217.617.016.122.527.023.022.020.020.519.016.617.118.618.719.821.826.020.220.518.417.3
Karnet14.514.616.216.415.916.515.511.912.015.914.614.014.520.225.022.520.517.817.015.012.715.115.816.417.019.223.617.417.815.614.7
Medina Research Centre18.017.418.218.618.620.219.015.216.618.618.017.616.222.028.022.720.620.918.416.517.019.119.120.322.626.5
Pearce RAAF17.216.017.217.718.020.117.714.715.118.818.118.818.323.426.824.220.320.220.319.015.617.518.218.719.421.725.622.721.619.117.3
Perth Airport17.716.718.018.418.420.118.615.214.718.618.218.317.323.427.423.420.719.920.118.616.217.619.019.019.621.525.522.221.918.917.0
Perth Metro18.117.018.318.118.319.918.315.215.518.818.317.217.123.127.023.320.620.120.218.416.217.318.819.019.521.325.121.621.318.717.6
Rottnest Island16.815.316.216.818.019.418.615.716.418.816.916.916.218.025.321.320.619.419.918.216.916.216.117.219.421.224.420.220.617.717.4
Swanbourne19.118.019.719.219.720.918.815.416.818.919.018.417.419.828.022.720.620.620.618.316.317.519.419.320.422.226.321.021.318.918.2
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 2015
12345678910111213141516171819202122232425262728293031
Bickley8.55.85.56.26.66.08.48.12.56.28.06.910.37.09.011.213.311.711.39.98.04.64.87.25.06.57.711.711.110.06.9
Garden Island HSF12.610.19.810.69.411.412.612.56.69.212.59.912.811.411.314.415.816.016.112.013.05.09.39.89.911.412.114.115.114.611.3
Gosnells City10.15.55.59.88.510.012.910.03.15.010.26.57.611.112.611.511.611.04.57.910.59.812.013.013.512.811.99.9
Jandakot Aero10.72.62.47.04.77.212.26.81.97.49.03.711.15.06.57.815.212.612.712.010.22.12.47.97.05.34.611.512.811.39.4
Karnet8.94.55.26.97.69.57.2-0.51.57.74.210.04.66.87.813.912.010.19.56.51.25.97.06.16.48.79.011.110.25.9
Medina Research Centre11.57.03.38.05.18.812.310.92.47.79.65.610.46.77.911.715.414.214.512.711.04.04.58.08.19.06.111.6
Pearce RAAF11.62.31.18.45.68.711.87.83.96.09.43.29.85.112.39.315.612.511.911.99.83.67.79.49.711.512.610.29.712.27.2
Perth Airport11.74.14.28.06.28.811.98.23.37.69.64.712.98.312.711.615.411.610.111.610.04.06.69.58.69.811.612.411.111.46.9
Perth Metro11.76.04.38.26.69.612.18.44.68.010.15.511.86.17.99.115.412.213.311.59.74.35.28.78.17.99.111.712.313.88.7
Rottnest Island12.611.110.911.810.512.213.112.27.39.713.912.212.912.614.115.913.415.514.011.412.69.210.210.710.912.914.116.315.914.411.9
Swanbourne10.36.16.29.18.110.011.812.45.49.011.18.612.68.211.813.115.315.313.811.411.77.07.19.49.29.911.512.013.614.29.8
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 2015
12345678910111213141516171819202122232425262728293031
Anketell 1.8 - - - - - 0.6 15.8 8.8 2.0 2.4 - - 2.0 - - 12.4 17.0 0.6 15.6 6.4 17.0 0.2 - - - - - 10.2 17.2 0.6
Bickley 0.2 - - - - - 4.0 9.8 20.4 5.2 5.2 - 0.2 - 0.2 - 10.0 10.8 2.2 39.6 3.2 16.0 1.6 - 0.2 - - - 2.0 12.6 0.2
Bungendore - - - - - - 2.0 12.2 13.2 1.0 3.8 0.2 - 0.4 0.2 - 13.6 22.2 -
2.8 14.6 1.0 0.2 - - - 0.2 1.2 22.0 0.2
Chidlow 9.2 - - - - - 7.2 4.8 13.0 - 7.2 - - - 6.6 6.2 2.6 24.8 - 7.8 - - - - - - 9.2 10.8
Garden Island HSF 0.2 - - - - - - 14.2 5.6 2.2 2.0 - 0.6 2.6 - - 13.0 2.4 - 12.0 5.6 17.2 0.2 - - - - 1.8 4.2 7.8 1.2
Gidgegannup 1.4 - - - - - 7.2 1.4 11.2 2.0 2.6 - - - - - 5.4 7.8 3.4 30.6 3.2 17.6 0.2 - - - - - 1.6 13.6 0.2
Gosnells City 0.1 - - - - - 1.2 6.4 3.4 - - - 8.8 11.0 2.0 22.8 3.0 12.0 - - 5.0 11.2 0.4
Jandakot Aero 1.6 - - - - - 0.8 21.0 6.8 1.2 6.0 - - 0.4 - - 10.4 12.6 0.4 27.4 6.8 11.0 0.2 - - - - - 7.2 17.8 -
Jarrahdale 2.8 - 0.4 - - 0.2 1.4 11.2 13.4 0.4 2.6 - - 0.6 0.2 - 10.8 15.8 -
6.2 20.2 0.4 - - 0.2 0.2 - 6.0 22.4 0.4
Karnet 4.6 - - - - - 1.2 18.4 17.8 12.0 4.2 0.1 0.1 0.5 - - 11.0 10.0 6.0 25.2 8.5 16.0 - - - - - 12.4 19.2 -
Karragullen North 0.2 - - - - - 2.2 8.6 11.6 3.0 3.0 0.2 - - - - 11.2 15.4 2.4 24.0 4.0 16.6 1.0 0.2 - - - - 1.8 14.0 0.4
Maida Vale - - - - - - 1.8 9.4 8.0 7.8 8.0 0.2 - - - - 7.2 7.0 2.0 26.6 3.2 19.4 0.2 - - - - - 2.0 11.8 1.8
Midland - - - - - - - 18.2 - - - - 7.4 4.1 2.4 20.8 5.2 11.2 - - - - 13.7
Mount Helena 20.4




7.0 5.4 7.8 5.0 5.2




5.8 7.0 4.4 24.8 3.6 12.8 0.2




3.2 8.4
Mundaring 6.0 - - - - - 4.6 8.6 8.4 5.4 9.2 0.2 - - - - 8.4 9.6 3.0 26.0 2.0 16.0 0.2 0.2 - - - - 28.0 12.4
Pearce RAAF 2.0 - - - - - 4.6 0.4 13.0 1.6 3.4 - - - - - 5.4 7.0 5.6 14.8 4.8 16.8 - - - - - - 3.2 10.8 -
Perth Airport 0.4 - - - - - 1.0 5.0 7.0 3.6 3.8 - - - - - 6.8 3.6 2.4 25.6 3.0 22.4 - - - - - - 1.2 11.6 -
Perth Metro 0.2 - - - - - 1.0 6.4 12.6 4.0 3.8 - - - - - 5.6 5.0 1.0 16.8 7.0 29.6 - - -
- - 4.2 15.6 0.2
Pickering Brook





3.0 10.8 17.8 3.0 7.4




9.6 12.0 3.4 28.8 2.6 18.4 1.0




1.4 12.6
Roleystone - - - - - - 3.2 7.1 21.5 3.6 3.1 - - - - - 10.8 20.2 2.2 25.6 4.2 18.6 - 0.8 - - - - 2.4 16.1 0.4
Rottnest Island - - - - - - 0.2 14.4 7.4 7.0 0.4 - 0.6 2.0 - - 7.6 2.6 0.2 12.0 2.8 15.8 0.8 - - - - 16.6 9.6 4.2 0.2
Serpentine 1.6 - - - - - 0.2 11.8 9.6 3.6 4.2 - - - - - 9.4 11.4 0.2 19.6 7.4 18.2 0.6 0.2 - - - - 4.2 13.0 -
Swanbourne 0.4 - - - - - 1.2 7.2 8.6 6.0 3.6 - - 0.2 - - 7.2 10.6 0.4 14.6 8.8 19.2 1.0 - - - - - 2.0 15.0 -
Werribee 0.4 - - 0.2 - - 7.0 3.2 9.4 2.2 2.0 0.2 - - - 0.2 6.0 6.0 2.8 13.0 2.0 13.0 1.6 0.2 - - - - 4.8 5.0 -
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 lists 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.

A climate summary is generally published on the first working day of each month.

This statement has been prepared based on information available at 9 am on Tuesday 1 September 2015. Some checks have been made on the data, but it is possible that results will change as new information becomes available.

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.

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.

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.

The ACORN-SAT dataset is used for temperature area averages.

Further information

Media
(03) 9669 4057
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