Perth in April 2016: Mild nights and above average rainfall

Mean minimum temperatures in April 2016 were generally 1 °C to 2 °C warmer than normal across the Perth Metropolitan area, while mean maximum temperatures were mostly near average. Rainfall was above average for most sites.

  • Below average maximum temperatures
  • Above average minimum temperatures;
  • Generally above average rainfall; wettest April at Perth Metro for four years

Rainfall in April 2016 was above average for much of the Perth metropolitan area. Monthly rainfall totals were between 30 mm and 90 mm across the coastal plain and on offshore islands, and between 100 mm and 110 mm in the hills. The highest April rainfall total in Perth was 110.8 mm at Karragullen North, while Gidgegannup had its wettest April for 29 years. Perth Metro recorded a monthly total of 68.2 mm on 13 rain days, which is its wettest April for four years, since 2012, when 69.2 mm was recorded. April 2016 was also the wettest April in terms of rain days at Perth Metro for eight years, since 2008, when 13 rain days were recorded. Perth Metro on average records seven rain days in April.

Perth saw a dry start to April until a slow moving trough near the west coast produced frequent showers between the 9th and 12th. A cold front, middle level trough and associated cloudband tracked over the State's southwest from the 17th to19th, bringing widespread moderate rainfall to the Perth area. A cold front produced light to moderate rainfall across Perth on the 25th (ANZAC Day) and a westerly flow in its wake with embedded fronts brought further light falls to conclude the month.

Mean maximum temperatures were mostly 1 °C to 2 °C cooler than normal in the Perth area, with mean maxima ranging in the mid-twenties for the coastal plain and offshore islands, and to the low twenties in the hills. Days were mostly mild with warm to hot days on the 2nd and 3rd, 15th and 16th, and 22nd to 24th. The hottest days were the 3rd and 16th, with daily maxima mostly in the low-to-mid thirties on the coastal plain. The coolest days were the 27th and 30th, with daily maxima in the mid-to-high teens across Perth. Perth Metro recorded a daily maximum temperature of 19.5 °C on the 27th, which was its coolest day for 2016 so far.

Mean minimum temperatures were generally 1 °C to 2 °C higher than normal across the Perth area, with mean minima in the mid-teens. Most nights were mild, with very mild conditions from the 11th to 13th, whilst cool nights were recorded on the 27th and 28th. A mean minimum temperature of 15.3 °C at Perth Metro is the second highest since the current Mount Lawley site opened in 1993, only behind a mean minimum of 16.7 °C in April 2013.

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Extremes in April 2016
Hottest day 34.3 °C at Pearce RAAF on the 3rd
Warmest days on average 25.3 °C at Gosnells City
Coolest days on average 21.8 °C at Bickley
Coldest day 15.1 °C at Bickley on the 27th
Coldest night 7.1 °C at Karnet on the 28th
7.9 °C at Bickley on the 27th
Coolest nights on average 13.4 °C at Bickley
Warmest nights on average 17.4 °C at Rottnest Island
16.3 °C at Gosnells City
16.3 °C at Swanbourne
Warmest night 22.0 °C at Gosnells City on the 11th
Warmest on average overall 20.7 °C at Gosnells City
Coolest on average overall 17.6 °C at Bickley
Wettest overall 110.8 mm at Karragullen North
Driest overall 33.8 mm at Garden Island HSF
Wettest day 38.4 mm at Karragullen North on the 19th
Strongest wind gust 74 km/h at Swanbourne on the 26th

Highest April total rainfall for at least 20 years
Observed
(mm)
Most recent
higher
Average for
April
Gidgegannup 81.2 89.0 in 1987* 45.1

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




Summary statistics for April 2016
Maximum temperatures
(°C)
Minimum temperatures
(°C)
Rainfall
(millimetres)
Mean for
April
2016
Diff
from
average
Highest for
April
2016
Mean for
April
2016
Diff
from
average
Lowest for
April
2016
Total for
April
2016
Average
for
April
Rank of
April
2016
Fraction of
April
average
Bickley 21.8 -1.8 31.0 3rd 13.4 +0.7 7.9 27th 105.4 56.7 high 186%
Garden Island HSF 23.6 -0.3 30.2 16th 17.0 +0.9 11.5 27th 33.8 41.0 average 82%
Gosnells City 25.3 -1.2 34.0 3rd 16.3 +1.5 10.0 28th 57.8 44.0 average 131%
Jandakot Aero 24.9 -0.9 33.0 3rd 14.3 +1.9 8.6 28th 62.2 42.8 average 145%
Pearce RAAF 25.1 -1.3 34.3 3rd 14.9 +1.5 8.9 28th 68.2 35.3 v high 193%
Perth Airport 25.0 -0.6 33.9 3rd 14.6 +1.6 9.2 6th 57.0 41.0 average 139%
Perth Metro 25.0 -0.9 33.8 3rd 15.3 +1.5 10.1 27th 68.2 43.8 high 156%
Rottnest Island 23.3 -0.5 29.4 16th 17.4 +0.1 11.9 27th 46.8 35.6 high 131%
Swanbourne 24.3 -1.2 32.3 16th 16.3 +1.1 10.1 27th 90.8 41.5 v high 219%
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 April 2016
123456789101112131415161718192021222324252627282930
Bickley23.927.931.023.319.221.121.724.421.823.119.921.522.621.122.828.620.619.721.621.421.623.025.725.117.717.315.116.817.916.1
Garden Island HSF22.022.926.422.521.423.523.625.524.128.423.924.923.921.227.030.223.722.522.021.125.325.829.324.621.920.419.420.421.218.1
Gosnells City26.530.534.026.222.824.525.428.624.827.323.825.525.823.226.532.024.523.125.025.025.526.730.327.121.121.019.021.221.920.2
Jandakot Aero25.529.433.025.722.423.825.028.224.227.124.025.825.622.826.532.223.522.524.124.325.226.629.925.621.021.018.321.021.919.6
Karnet22.521.923.027.223.617.515.215.917.518.516.0
Pearce RAAF26.231.134.325.922.224.225.625.425.027.021.926.626.724.225.732.625.522.024.524.724.726.229.229.220.920.818.321.021.918.9
Perth Airport26.030.833.926.322.124.324.927.424.626.523.624.925.423.525.932.724.523.224.625.125.226.329.627.021.020.818.620.621.119.6
Perth Metro25.330.533.825.122.424.324.827.524.126.523.725.024.923.826.732.624.423.324.324.525.526.130.026.521.021.519.520.921.419.6
Rottnest Island23.424.029.324.220.921.923.426.923.125.622.922.623.422.124.029.423.722.621.821.523.725.028.524.621.021.018.620.521.518.6
Swanbourne23.826.628.625.222.023.924.828.123.027.123.925.123.223.126.632.322.522.822.322.325.226.730.424.820.621.519.221.321.719.1
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 April 2016
123456789101112131415161718192021222324252627282930
Bickley14.213.015.416.49.99.210.012.514.614.317.216.417.913.813.313.716.615.314.312.211.310.912.717.417.214.67.99.311.88.9
Garden Island HSF18.616.415.420.815.313.114.517.217.918.620.719.719.314.015.818.919.219.916.015.914.716.618.819.219.917.711.512.617.013.4
Gosnells City16.015.818.916.213.113.115.018.019.219.222.020.020.714.716.520.016.414.414.415.018.117.619.317.310.210.012.912.5
Jandakot Aero13.612.614.213.310.39.012.315.116.017.820.418.918.512.511.018.616.614.615.210.711.014.716.316.818.817.28.78.614.410.9
Karnet11.412.314.515.116.514.58.57.111.19.0
Pearce RAAF13.512.515.013.612.711.814.016.317.517.219.519.018.712.513.219.216.614.615.410.614.616.318.114.418.516.910.78.912.511.5
Perth Airport14.212.914.913.213.09.213.814.516.817.319.818.819.912.713.017.717.714.115.811.612.514.716.315.418.716.89.99.510.811.0
Perth Metro15.814.115.515.313.210.213.715.917.617.420.818.920.013.913.918.017.815.515.413.012.414.617.015.918.817.510.110.813.012.4
Rottnest Island18.817.517.719.715.213.915.017.618.818.320.219.619.118.816.518.819.918.516.916.816.617.018.920.219.417.111.913.416.213.9
Swanbourne18.514.416.518.013.011.513.816.418.117.120.718.919.616.115.118.318.919.216.313.914.515.318.020.119.016.910.112.516.212.1
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 April 2016
123456789101112131415161718192021222324252627282930
Anketell 0.4 - - - - - - - - 5.4 - 1.8 0.8 - 3.0 - 1.8 1.2 25.0 - - - - - 2.2 6.0 2.2 1.4 1.8 7.8
Bickley - - -
- - - - - 11.6 - 9.8 3.0 0.2 - 0.2 2.0 1.8 33.4 0.4 - - - - 1.0 21.4 8.8 1.2 5.8 4.8
Bungendore - 0.2 - - - - - - - 11.4 4.0 5.2 2.0 0.2 - - 1.2 1.6 21.6 0.2 - - - - 0.6 7.4 1.8 1.8 6.6 4.6
Chidlow - - - - - - - - - 8.0 13.2 11.2 - - - 2.4 8.0 - - - - - - 17.2 4.6 0.6 5.6 3.2
Garden Island HSF 0.8 - - - - - - - - 1.0 0.8 1.0 - - 0.2 - 0.6 3.0 13.0 - - - - - 3.4 2.2 2.6 0.4 2.4 2.4
Gidgegannup - - - - - - - - - 7.8 - 11.8 4.0 0.2 - - - 2.2 9.0 0.2 0.2 - - - 0.6 18.4 13.4 1.8 8.6 3.0
Gosnells City - - - - - - - - - 3.5 - 4.9 4.0 - - - 1.2 21.2 15.8 2.8 1.8 1.2 1.6
Jandakot Aero - 0.2 - - - - - - - 6.8 0.2 2.4 1.0 - - - 1.0 1.6 21.6 - - - - - 4.6 14.6 1.8 2.8 2.2 1.4
Jarrahdale 0.2 0.2 0.2 - - - - - - - 2.8 3.0 1.6 0.2 0.2 - 1.2 15.6 17.0 - 0.2 - - - 4.0 16.6 4.8 1.2 3.6 10.8
Karnet



















- - - - 7.8 18.2 2.6 0.8 6.0
Karragullen North - - - - - - - - - 7.6 0.4 6.6 2.4 - - - 1.6 2.0 38.4 0.2 - - - - 1.8 31.6 7.0 2.0 5.2 4.0
Maida Vale - - - - - - - - - 4.6 0.4 6.8 3.4 - - - 2.2 0.4 30.2 0.2 - - - - 2.4 13.4 2.2 2.4 2.4 2.6
Midland - - - - - - - - - - - 10.8 1.0 - - - - - 15.2 - - - - - - 16.2 - 2.8

Mount Helena








7.0
12.2 11.0


2.0 6.2 7.2




0.4 17.4 6.0 1.4 5.2 2.6
Mundaring - - - - - - - - - 10.4 - 9.2 2.8 - 0.2 - 0.4 3.0 11.2 0.4 - - - - 3.4 23.6 4.6 2.0 3.4 6.6
Pearce RAAF - - - - - - - - 0.4 14.2 0.2 8.0 1.6 0.2 - - - 3.2 17.6 - - - - - 0.6 7.6 4.0 1.0 6.8 2.8
Perth Airport - - - - - - - - - 3.6 0.2 5.4 2.0 - - - 0.6 0.4 23.2 - - - - - 2.8 11.6 2.2 0.6 2.0 2.4
Perth Metro - - - - - - - - - 11.2 0.2 5.0 3.4 - - - 1.6 - 25.8 0.2 - - - - 2.6 9.2 2.0 2.0 1.2 3.8
Pickering Brook








10.6
7.8 4.0


2.0 2.6 27.5




1.6 34.4 8.2 2.6 7.4
Roleystone - - - - - - - - - 7.4 1.8 6.0 2.6 - - - 2.4 1.6 36.0 - - - - - 2.8 22.4 6.2 1.1 4.4 4.7
Rottnest Island 0.2 0.6 - - - - - - - 7.2 2.0 0.8 1.2 - 0.6 - 0.2 1.2 17.0 - - - - - 1.6 3.2 5.0 2.0 2.4 1.6
Serpentine 0.8 - - - - - - - - - 5.2 1.4 1.6 - 0.8 - 1.0 10.4 12.8 - - - - - 13.2 5.2 3.2 1.0 2.4 9.2
Swanbourne - - - - - - - - - 10.2 - 3.0 7.2 - - - 1.2 0.6 26.0 - - - - - 15.0 18.0 2.2 1.2 1.2 5.0
Wanneroo - - - - - - - - 15.0 3.8 - - 0.4 28.2 - - - - - - 18.4 10.0 0.8 2.6
Werribee - - - - - - - - - 4.6 2.0 14.8 2.6 - - - - 1.0 4.8 - 0.2 - - - 0.6 10.2 4.4 0.6 4.4 3.2
Whiteman Park - - - - - - - - 9.2 - - 7.0 1.4 - - - - - 9.8 - - - - - 4.2 14.4 4.2 1.4

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 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 Monday 2 May 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

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(03) 9669 4057
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