Perth in May 2016: a cool, wet month

May was a month dominated by westerly winds, cold fronts, and rain in the Perth metropolitan area. Temperatures were well below average, and rain was frequent.

  • Cool weather dominated the month
  • Coolest since 1992 for some metropolitan sites
  • Rain above average for May
  • Nine consecutive wet days from the 21st

Unlike much of Western Australia, Perth (and much of the southwest) had a cool May. Cold fronts and westerly winds ensured below-average temperatures were dominant. Averaged across the month, daytime maximum temperatures were below average, typically by one to two degrees. The warmest weather, on the 11th and 12th, only saw temperatures reach the mid-20s. Overnight temperatures were also down on the May average, although generally by less than half a degree. The mornings of the 8th, 12th and 31st were especially chilly, with several sites dropping below 5 °C. Some sites in the greater Perth area had their coolest May since 1992, and Perth Metro recorded its coolest May since 1997.

Rain was also a common feature of Perth's weather during May, with many wet days right through the month. Overall totals were about 10 to 20% above average, but it was the persistence of rain in the latter part of the month that was notable: most metropolitan sites recorded some rain on every day from the 21st to the 29th. The nine consecutive rain days at Perth Metro was the third-longest May wet spell at the site in the past 45 years. There were some moderate to heavy falls, with some daily totals over 30 mm to 9 am on both the 21st and 24th. A strong cold front that passed through the metropolitan area early on the 21st brought damaging wind gusts over 100 km/h, and a storm tide with some minor inundation along the Swan River.

Further information

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Extremes in May 2016
Hottest day 26.3 °C at Pearce RAAF on the 11th and 12th
Warmest days on average 21.1 °C at Gosnells City
Coolest days on average 17.6 °C at Bickley
Coldest day 13.7 °C at Bickley on the 21st
Coldest night 2.1 °C at Jandakot Aero on the 8th
Coolest nights on average 7.7 °C at Karnet
Warmest nights on average 14.9 °C at Rottnest Island
Warmest night 18.3 °C at Rottnest Island on the 14th
Warmest on average overall 17.6 °C at Rottnest Island
Coolest on average overall 13.7 °C at Bickley
Wettest overall 177.8 mm at Jarrahdale
Driest overall 68.8 mm at Rottnest Island
Wettest day 44.6 mm at Bungendore on the 24th
Strongest wind gust 109 km/h at Rottnest Island on the 21st

Record lowest May mean daily maximum temperature
New record
(°C)
Old
record
Years of
record
Average for
May
Swanbourne 20.5 20.6 in 1997 22 22.2

Lowest May mean daily maximum temperature for at least 20 years
Observed
(°C)
Most recent
lower
Average for
May
Karnet 18.1 18.0 in 1992 19.2
Perth Airport 20.8 20.5 in 1992 21.8
Gosnells City 21.1 21.0 in 1992* 22.7

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




Record lowest May mean temperature
New record
(°C)
Old
record
Years of
record
Average for
May
Gosnells City 15.7 15.9 in 2015 23 17.2

Lowest May mean temperature for at least 20 years
Observed
(°C)
Most recent
lower
Average for
May
Pearce RAAF 14.7 14.5 in 1987 16.4



Summary statistics for May 2016
Maximum temperatures
(°C)
Minimum temperatures
(°C)
Rainfall
(millimetres)
Mean for
May
2016
Diff
from
average
Highest for
May
2016
Mean for
May
2016
Diff
from
average
Lowest for
May
2016
Total for
May
2016
Average
for
May
Rank of
May
2016
Fraction of
May
average
Bickley 17.6 -1.7 22.9 12th 9.7 -0.5 6.1 30th 156.6 132.2 high 118%
Garden Island HSF 19.9 -1.5 22.6 11th 13.7 -0.3 9.3 12th 81.6 78.6 high 104%
Gosnells City 21.1 -1.6 26.1 12th 10.4 -1.4 6.2 12th 126.2 104.7 high 121%
Jandakot Aero 20.6 -1.4 25.0 11th 8.7 -0.7 2.1 8th 137.0 108.0 high 127%
Karnet 18.1 -1.1 22.6 11th 7.7 -1.4 3.5 31st 162.6 141.6 average 115%
Medina Research Centre 21.1 -1.0 24.6 12th 9.6 -0.9 3.5 8th 127.2 99.3 high 128%
Pearce RAAF 20.8 -1.2 26.3 12th 8.7 -2.1 2.6 8th 90.2 85.0 average 106%
Perth Airport 20.8 -1.0 26.2 12th 9.5 -0.9 3.1 8th 102.0 99.4 average 103%
Perth Metro 20.8 -1.5 25.5 12th 10.1 -0.5 4.6 8th 112.0 116.9 average 96%
Rottnest Island 20.2 -0.9 23.1 12th 14.9 -0.4 10.5 22nd 68.8 75.7 average 91%
Swanbourne 20.5 -1.7 23.4 12th 12.1 -0.5 8.1 31st 111.6 92.5 high 121%
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 May 2016
12345678910111213141516171819202122232425262728293031
Bickley15.917.017.619.717.016.815.213.918.720.522.722.919.419.018.917.918.619.916.218.613.715.817.315.916.615.617.717.015.816.6
Garden Island HSF18.520.520.122.019.820.118.316.018.821.522.622.422.121.321.620.320.121.119.421.519.119.520.018.918.618.420.219.616.918.818.5
Gosnells City19.721.622.521.421.018.517.021.423.225.826.123.522.022.521.521.923.020.022.617.519.820.819.520.018.721.420.519.719.820.6
Jandakot Aero19.221.921.322.220.719.918.816.820.522.625.024.323.021.722.120.820.921.419.921.517.719.720.519.418.818.820.520.218.518.920.1
Karnet15.819.019.717.616.516.013.918.921.022.622.520.219.419.118.718.219.817.919.114.418.316.416.715.717.917.216.416.818.0
Medina Research Centre21.721.721.922.222.220.518.517.120.823.124.324.624.022.022.321.421.522.120.723.018.520.021.219.420.118.821.419.819.619.820.2
Pearce RAAF19.120.620.622.121.419.519.216.620.322.626.326.323.222.022.121.322.022.519.122.016.819.920.519.518.820.020.720.318.919.120.0
Perth Airport19.121.121.022.021.620.218.817.420.922.925.826.222.922.621.821.021.622.819.322.017.219.420.319.418.919.120.720.018.719.620.8
Perth Metro19.420.621.522.321.020.318.617.020.922.825.525.522.722.322.421.221.522.019.822.017.519.620.619.519.219.820.720.019.320.020.6
Rottnest Island18.521.120.421.520.220.318.716.619.722.423.122.721.922.720.720.721.819.922.118.219.620.119.619.519.120.519.717.118.718.8
Swanbourne19.120.521.922.321.420.417.916.620.022.023.323.422.121.722.421.021.321.519.621.518.420.120.619.419.919.721.219.818.919.619.4
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 May 2016
12345678910111213141516171819202122232425262728293031
Bickley9.69.410.79.911.611.49.96.46.79.39.310.712.113.610.79.09.913.212.010.413.27.19.610.78.210.66.410.18.16.16.1
Garden Island HSF13.512.514.216.117.414.714.511.411.912.912.59.316.518.115.313.815.815.415.611.915.911.613.815.213.314.811.514.111.510.010.5
Gosnells City11.89.510.111.413.411.510.56.69.06.29.414.68.98.47.912.913.39.414.79.811.013.69.611.67.011.711.510.16.6
Jandakot Aero11.38.47.79.79.012.110.32.13.35.45.43.79.014.28.46.87.313.212.18.115.110.111.413.49.311.54.511.68.84.13.6
Karnet7.06.68.08.89.89.05.83.66.46.05.69.58.15.76.313.011.07.712.95.212.07.810.54.09.24.63.5
Medina Research Centre9.08.911.69.912.011.13.54.66.38.05.09.416.011.09.18.113.012.68.212.511.713.110.712.56.613.09.05.46.1
Pearce RAAF10.16.57.57.511.012.011.52.63.14.97.73.87.912.95.87.56.69.911.97.014.77.89.613.69.611.66.210.410.89.97.9
Perth Airport9.68.07.510.011.812.710.83.13.66.68.66.98.813.88.78.27.511.912.38.614.89.510.313.09.911.58.211.49.49.98.0
Perth Metro12.89.99.711.211.613.212.44.65.07.07.36.010.513.910.29.48.912.513.19.115.110.510.613.210.112.87.012.511.07.35.0
Rottnest Island15.014.816.516.516.915.610.813.413.614.715.413.917.518.317.415.616.017.216.815.314.910.515.116.213.814.213.915.413.111.812.8
Swanbourne13.711.612.714.014.013.912.88.58.710.211.210.112.217.313.711.210.613.613.811.815.411.111.514.112.814.39.313.211.88.68.1
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 May 2016
12345678910111213141516171819202122232425262728293031
Anketell - - 0.2 - 0.2 0.6 22.0 1.2 - - - - - 8.0 - 6.2 - 1.6 - - 30.0 10.6 15.4 35.0 2.6 4.0 0.6 8.0 2.2 - -
Bickley - - 0.4 0.2 0.2 1.4 17.4 3.0 - 0.2 0.2 - 0.2 2.6 0.4 1.2 - 2.4 0.2 - 38.6 19.0 7.6 42.0 0.4 5.6 3.0 10.0 0.2 - 0.2
Bungendore 0.2 - 0.4 - 0.4 - 25.2 2.2 0.2 0.2 0.2 0.2 0.2 11.2 0.2 5.0 - 2.4 - 0.2 37.2 17.4 5.6 44.6 1.0 4.4 0.4 9.4 4.0 - -
Chidlow - - - - - - 14.0 1.4 - - - - 2.6 0.2 - 0.2 - - 31.4 16.8 14.6 0.8 4.2 - 2.6


Garden Island HSF - - - - 0.2 0.8 13.8 1.6 - - - - - 4.8 - 2.4 - 2.4 - - 16.8 6.0 1.6 19.8 0.4 2.4 1.8 4.4 2.4 - -
Gidgegannup 0.2 - 0.2 0.2 0.2 - 15.0 6.2 0.2 0.2 - - - 4.0 1.0 0.4 - - - - 30.4 23.0 0.6 25.6 0.4 5.0 0.6 3.8 0.8 - -
Gosnells City - - - - - 0.2 19.2 7.8 - - - - - - 0.1 1.4 - 1.4 - - 27.0 15.0 2.6 31.0 0.8 5.6 4.9 9.2 - - -
Herne Hill 2.8 - - - 0.2 - 21.0 1.9 - - - - 0.8 2.9 0.4 0.4 - - - - 28.8 16.8 1.0 14.6






Jandakot Aero - - 0.2 - - 0.4 17.6 0.8 - - - - - 7.2 0.2 - - 4.0 - - 28.0 12.6 6.2 38.4 0.8 5.8 0.6 14.2 - - -
Jarrahdale - 0.4 0.2 0.2 0.2 3.8 13.0 0.2 0.2 0.2 0.4 0.2 - 9.6 1.0 1.0 0.2 0.8 0.2 0.2 35.2 24.4 17.6 42.8 2.2 6.6 1.0 13.0 2.6 0.2 0.2
Karnet - 0.1 0.2
0.2 2.7 17.4 11.9 0.6 2.4 - 3.0 3.1 - 34.0 19.8 46.8 1.6 6.6 0.2 12.0


Karragullen North - - - - - - 27.2 1.0 - - - - - 6.2 0.4 1.2 - 3.2 - - 26.6 14.6 7.6 42.2 1.6 3.4 - 8.4 1.2

Maida Vale - - 0.2 - 0.2 0.6 13.4 3.9 0.1 0.2 - - 0.2 4.2 0.6 2.6 0.1 - 1.8 0.1 36.6 16.8 4.6 26.2 1.4 5.6 2.0 6.4 0.8

Medina Research Centre 5.4 0.4 - 0.4 0.8 22.2 1.0 - - - - - 4.6 - 4.4 - 2.8 0.1 - 25.0 7.4 8.4 32.6 1.2 2.0 0.8 5.6 2.0 0.1 -
Midland 1.2 0.1 - - 0.6 16.8 0.2 - - - 3.8 - 0.4 - - 50.4 19.8 0.4 3.2 0.2 1.8 -
Mount Helena





18.0 2.0




5.2 0.2

0.4

36.8 26.1 1.0 20.0 0.8 5.6 0.4 4.6 0.4

Mundaring - - - - 0.6 0.4 11.8 3.0 - 0.2 - - 0.2 - - - - 0.6 - - 40.6 25.0 4.8 25.4 1.4 4.4 - 4.2 0.4
Pearce RAAF - - - - - - 12.2 5.0 0.2 - - - - 2.4 0.6 1.6 0.2 - - - 27.4 12.0 - 16.2 0.6 3.6 0.2 7.6 0.4 - -
Perth Airport - - - - 0.2 - 12.6 0.8 - - - - - 3.6 0.2 1.2 - 2.2 - - 35.0 14.0 4.8 18.6 2.2 2.4 0.6 3.2 0.4 - -
Perth Metro - - 0.2 - - 1.6 18.0 1.2 - - - - - 4.6 - 2.2 - 3.6 - - 36.4 8.6 2.8 23.8 2.6 2.2 0.4 3.4 0.4 - -
Pickering Brook





19.6 3.0




1.2
4.2
1.6

31.4 18.8 7.6 33.4 1.0
2.2



Roleystone - - - - - 1.3 23.9 1.8 - - - - - 7.2 - 1.1 - 3.6 - - 32.0 17.4 9.1 39.4 1.2 3.1 2.1 7.7


Rottnest Island - - - - 0.4 1.4 7.2 1.4 -

0.2 - 0.6 - 1.0 - - - - 16.2 5.2 1.6 18.4 - 3.8 0.6 2.8 8.0 - -
Serpentine - - 0.2 - - 1.2 10.2 0.2 - - - - - 11.4 0.6 0.2 - 2.0 - - 27.6 18.0 10.2 31.0 2.0 5.6 1.4 8.8 2.2 0.2 -
Swanbourne - - 0.4 - 0.2 4.0 13.4 3.0 - 0.2 - - 0.2 3.2 - 0.2 - 6.2 - - 25.8 9.4 7.2 30.2 1.0 2.6 0.2 4.2 - - -
Wanneroo 5.8 - - - 0.5 19.8 - - - - 9.4 - 0.4 - - 40.6 16.2 1.0 6.6 0.8 15.4
Werribee - - - 0.2 0.4 - 13.8 1.2 0.2 - - 0.2 - 2.6 3.0 0.2 - - - 2.4 20.6 16.6 - 18.6 0.4 2.0 0.4 3.8 0.6 - -
Whiteman Park - - - - - 1.8 24.0 0.4 - - - - - 3.0 - - - - - - 36.0 14.6 3.2 17.8 0.8 5.4 0.6 4.0 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 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 12 pm on Wednesday 1 June 2016. 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
Enquiries