Greater Perth in December 2018: a dry month

December 2018 was dry with monthly rainfall totals generally less than 5 mm across Perth. Days and nights were mostly mild with only a handful of very hot days.

Below average rainfall

  • Monthly rainfall totals were mostly 1-5 mm across Greater Perth
  • Perth Metro recorded 1.8 mm in total, which was 17% of average and driest December since 2014 when no measurable rainfall was recorded

Mean maximum temperatures above average at inland sites

  • Mean maximum temperatures were above average in inland sites, though below average along the coast and on offshore islands
  • Mean minimum temperatures were mostly close to average
  • For coastal plain sites, temperatures over 37 °C were observed on four days (3rd,14th, 21st and 22nd), and the hottest day of the month was the 22nd when temperatures climbed over 40 °C
  • Perth Metro recorded 41.2 °C on the 22nd, which was its highest temperature for 13 months since 26 January 2017 when a maximum 42.0 °C was recorded

Perth Metro

  • The mean daily maximum temperature for Perth Metro was 29.6 °C, which is 0.5 °C above the long-term average of 29.1 °C
  • The warmest day was 41.2 °C on the 22nd, and the coolest day was on the 6th when the temperature reached 22.8 °C
  • The mean daily minimum temperature for Perth Metro was 16.2 °C, which is 0.1 °C below the long-term average of 16.3 °C
  • The coldest morning was 12.3 °C on the 7th, and the warmest morning was on the 22nd when the minimum temperature was 23.5 °C

Further information

Media
(03) 9669 4057
Enquiries

Extremes in December 2018
Hottest day 42.1 °C at Pearce RAAF on the 22nd
Warmest days on average 32.1 °C at Pearce RAAF
Coolest days on average 24.3 °C at Rottnest Island
26.6 °C at Swanbourne
Coldest day 20.0 °C at Karnet on the 6th
Coldest night 6.8 °C at Pearce RAAF on the 7th
Coolest nights on average 14.1 °C at Bickley
14.1 °C at Pearce RAAF
Warmest nights on average 17.5 °C at Rottnest Island
17.1 °C at Mandurah
Warmest night 25.9 °C at Pearce RAAF on the 22nd
Warmest on average overall 23.1 °C at Pearce RAAF
Coolest on average overall 20.9 °C at Rottnest Island
21.3 °C at Bickley
Wettest overall 7.8 mm at Karnet
Driest overall 0.8 mm at Perth Airport
Wettest day 5.2 mm at Karnet on the 16th
Strongest wind gust 85 km/h at Jandakot Aero on the 14th




Summary statistics for December 2018
Maximum temperatures
(°C)
Minimum temperatures
(°C)
Rainfall
(millimetres)
Mean for
December
2018
Diff
from
average
Highest for
December
2018
Mean for
December
2018
Diff
from
average
Lowest for
December
2018
Total for
December
2018
Average
for
December
Rank of
December
2018
Fraction of
December
average
Bickley 28.5 +0.5 37.9 22nd 14.1 +0.5 9.8 1st 3.4 14.7 average 23%
Garden Island HSF 24.9 -0.5 38.7 22nd 17.2 0.0 13.5 6th 1.0 10.9 low 9%
Jandakot Aero 29.2 +0.1 40.5 22nd 14.7 0.0 10.0 7th 1.8 10.7 average 17%
Mandurah 26.8 -0.2 35.8 21st 17.1 0.0 13.5 6th 5.4 16.7 average 32%
Millendon (Swan Valley) 31.1   41.3 22nd 14.4   8.0 7th 3.0
Pearce RAAF 32.1 +1.7 42.1 22nd 14.1 -0.4 6.8 7th 2.4 11.1 average 22%
Perth Airport 30.3 +1.3 40.9 22nd 15.2 +0.3 9.0 7th 0.8 11.3 low 7%
Perth Metro 29.6 +0.5 41.2 22nd 16.2 -0.1 12.3 7th 1.8 10.9 low 17%
Rottnest Island 24.3 -0.7 37.9 22nd 17.5 -0.1 13.6 6th 4.4 11.3 average 39%
Swanbourne 26.6 -1.3 39.0 22nd 16.6 +0.1 12.8 7th 1.6 11.5 average 14%

Daily maximum temperatures for December 2018
12345678910111213141516171819202122232425262728293031
Bickley21.129.236.521.124.120.723.828.531.829.621.526.031.636.628.927.326.226.127.530.133.837.933.332.333.127.024.823.527.129.032.9
Garden Island HSF20.427.229.722.423.320.820.321.422.222.821.924.629.931.424.224.022.022.423.229.034.238.726.326.524.223.224.321.921.822.623.8
Gosnells City23.131.038.023.023.025.830.133.530.028.034.539.130.529.033.237.440.534.333.729.527.228.329.533.2
Jandakot Aero22.429.237.122.724.422.324.728.031.428.423.527.233.038.130.929.427.625.127.633.136.840.533.431.832.528.726.324.926.328.131.1
Karnet21.835.024.520.031.229.721.336.025.025.026.627.327.329.538.033.028.524.9
Mandurah21.826.733.023.122.221.522.925.129.225.522.925.030.133.524.925.425.324.424.831.735.835.529.729.828.026.524.124.925.424.428.1
Millendon (Swan Valley)23.732.339.824.026.423.526.531.833.531.123.927.935.139.830.030.429.027.730.433.137.441.335.634.735.529.727.426.429.730.834.3
Pearce RAAF25.033.141.025.526.824.127.433.135.532.924.828.735.540.431.031.928.828.431.133.937.942.136.535.736.931.428.427.330.832.235.5
Perth Airport23.731.238.423.525.122.825.929.932.429.923.727.734.339.931.031.128.026.428.433.336.940.934.933.633.829.627.126.028.029.732.2
Perth Metro23.030.037.823.424.922.825.128.630.028.823.426.833.439.129.129.726.825.427.933.337.241.234.732.733.528.226.725.427.628.931.6
Rottnest Island21.222.425.422.123.021.421.523.022.922.822.922.529.330.222.723.722.722.022.424.830.237.924.425.025.223.424.323.222.823.324.5
Swanbourne22.526.434.822.422.921.122.523.724.325.522.624.031.734.427.628.923.922.925.531.835.139.026.828.928.525.124.623.923.524.726.6
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 December 2018
12345678910111213141516171819202122232425262728293031
Bickley9.811.314.316.111.111.09.812.012.714.312.014.311.518.918.316.213.711.212.612.713.719.721.716.516.916.813.113.712.113.414.5
Garden Island HSF14.914.317.618.015.113.514.515.916.718.017.117.316.417.019.618.916.915.816.517.718.421.218.917.919.119.317.318.816.217.117.4
Gosnells City12.514.918.817.812.510.012.716.118.013.115.520.519.616.516.513.522.020.616.116.114.115.216.215.2
Jandakot Aero10.811.115.218.710.312.810.011.914.314.313.715.915.017.919.016.514.713.815.715.417.722.917.515.715.813.811.117.011.412.113.7
Karnet8.511.015.411.29.513.912.014.817.114.513.411.512.513.414.120.513.411.813.1
Mandurah14.713.717.918.514.813.514.315.216.517.416.216.915.820.119.518.216.215.416.116.918.022.722.417.319.118.217.018.315.716.316.7
Millendon (Swan Valley)8.711.314.418.610.512.98.09.112.214.014.516.615.318.217.915.216.514.713.914.918.123.016.414.216.014.612.617.611.311.412.8
Pearce RAAF8.89.715.518.011.812.96.810.611.713.114.316.416.417.317.214.915.414.113.215.419.025.916.013.114.714.511.716.99.710.512.0
Perth Airport9.413.116.918.99.913.09.010.216.016.214.516.215.417.820.016.216.615.215.216.617.723.817.415.516.614.812.717.911.811.713.9
Perth Metro12.913.816.318.813.513.112.312.516.015.515.116.915.617.820.117.416.515.416.217.017.723.519.317.517.016.816.118.312.813.416.5
Rottnest Island15.315.318.017.616.713.615.716.517.218.316.416.716.718.618.418.416.816.117.118.119.221.519.518.219.618.817.718.116.318.118.0
Swanbourne13.313.416.618.014.812.912.813.815.317.115.617.316.219.919.118.015.715.016.617.218.524.319.817.518.616.616.318.114.115.716.5
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 December 2018
12345678910111213141516171819202122232425262728293031
Anketell - - - - - 1.0 - - - - - 0.8 - - 0.2 0.6 - - - - - - - 1.4 - - - - - - -
Bickley - - - - - 2.4 - - - - - - - - - 1.0 - - - - - - - - - - - - - - -
Bungendore - - - - - 1.0 - 0.2 - - - - - - 0.2 0.2 - - - - - - - - - - - - - - -
Chidlow - - - - - 1.0
























Garden Island HSF - - - - - 0.2 - - - - - 0.2 - - 0.6 - - - - - - - - - - - - - - - -
Gidgegannup - - - - - 0.6 0.2 - - - - 0.4 - - - - - - - - - - - - - - - - - - -
Gosnells City - - - - - - - - - - - - - - 0.4 - - - - - - - - - - - - - - - -
Huntly - - - - - 3.0 - - - - - 2.2 - - 0.2 - 0.3 - - - - - - - - - - - - -
Jandakot Aero - - - - - 0.6 - - - - - 0.6 - - - 0.6 - - - - - - - - - - - - - - -
Jarrahdale - - - - - 3.2 0.2 - - - - 0.6 0.2 - 0.2 1.0 - - - - - - - - - 0.2 - - - - -
Karnet - - - - 1.4 - - - - - -

1.2 5.2 - - - - - - - - - - - -


Karragullen North - - - - - 1.4 - - - - - - - - - 0.8














Maida Vale - - - - - 1.0 - - - - - 0.6


















Mandurah - - - - - 0.2 - - - - - 2.0 - - - 3.2 - - - - - - - - - - - - - - -
Midland - - - - - 1.4
























Millendon (Swan Valley) - - - - - 2.4 - - - - - 0.4 0.2 - - - - - -
- - - - - - - - - - -
Mosman Park - - - - - 9.8
























Mount Solus - - - - - 4.2 - - - - - 1.0 - - 0.2 0.2 - - - - - - - - - - - - - - -
Muchea - - - - - 0.4 - - - - - 1.6 - - - - - - - - - - - - - - - - - - -
Mundaring - - - - - 2.2 - - - - - - - - 0.4















Noble Falls




1.8




0.2


















Pearce RAAF - - - - - 1.4 - - - - - 0.8 0.2 - - - - - - - - - - - - - - - - - -
Perth Airport - - - - - 0.6 - - - - - 0.2 - - - - - - - - - - - - - - - - - - -
Perth Metro - - - - - 1.6 - - - - - 0.2 - - - - - - - - - - - - - - - - - - -
Pinjarra South - - - - - 0.4 - - - - - 0.8 - - - 1.2 - - - - - - - - - - - - - - -
Roleystone - - - - - - - - - - - 0.6 - - - 0.6














Rottnest Island - - - - - 1.2 - - - - - - - - 0.2 - - - - - -
- 3.0 - - - - - - -
Serpentine - - - - - 1.8 - - - - - 0.6 - - - 0.6 - - - - - - - - - - - - - - 0.2
Swanbourne - - - - - 1.2 - - - - - 0.2 - - 0.2 - - - - - - - - - - - - - - - -
Wanneroo - - - - - 2.0
























Werribee - - - 0.8 - 1.6 - - - - - 0.2 0.2 - - - - - - - - - - - - - - - - - -
Whiteman Park - - - - - 2.2 - - - - - 0.8


















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 9 am on Wednesday 2 January 2019. 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