Greater Perth in January 2019: coolest January for over a decade

Both mean maximum and minimum temperatures were below average across Greater Perth. For Perth Metro and Perth Airport, it was the coolest January since 2007. Monthly rainfall totals were mostly less than 10 mm, and the lowest January rainfall for four years for most sites.

Below average rainfall

  • Monthly rainfall totals were mostly less than 10 mm, increasing to about 20 mm in the Perth hills; the lowest January rainfall since 2015 for most sites
  • Perth Metro recorded a monthly total of 7.2 mm over 4 days, which was its lowest January rainfall since a total of 0.2 mm in 2014
  • A cut-off low pressure system near the far southwest WA on the 23rd produced widespread light rainfall with moderate falls in the Perth hills

Cooler than average temperatures

  • Mean maximum temperatures were generally 1-3 °C below average across Greater Perth; while mean minimum temperature were mostly 1-2 °C below average
  • In terms of mean maximum temperature, Swanbourne had its coolest January on record, and Perth Metro's mean of 30.5 °C was its coolest January since 2007 when a mean of 29.1 °C was recorded
  • Perth Metro, Perth Airport, Pearce RAAF and Swan Valley recorded two consecutive days with temperature over 40 °C on the 19th and 20th; Perth Metro's 42.1 °C on the 20th was its highest January temperature for four years since a 44.4 °C was recorded on 5 January 2015
  • The coolest days were on the 23rd and 24th with daily maxima merely in the high 10s to low 20s
  • Perth Metro's mean minimum temperature of 16.6 °C equalled its January record low mean minimum set in 2007; Pearce RAAF had its lowest January mean minimum since 1990

Perth Metro

  • Total rainfall for Perth Metro was 7.2 mm, which is 37% of the long-term average of 19.7 mm
  • The mean daily maximum temperature for Perth Metro was 30.5 °C, which is 0.7 °C below the long-term average of 31.2 °C
  • The warmest day was 42.1 °C on the 20th, and the coolest day was on the 24th when the temperature reached 20.6 °C
  • The mean daily minimum temperature for Perth Metro was 16.6 °C, which is 1.5 °C below the long-term average of 18.1 °C
  • The coldest morning was 10.0 °C on the 4th, and the warmest morning was on the 6th when the minimum temperature was 20.3 °C

Further information

Media
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Extremes in January 2019
Hottest day 44.4 °C at Pearce RAAF on the 20th
Warmest days on average 33.1 °C at Pearce RAAF
Coolest days on average 24.6 °C at Garden Island HSF
Coldest day 17.3 °C at Bickley on the 24th
Coldest night 6.8 °C at Jandakot Aero on the 4th
Coolest nights on average 14.7 °C at Bickley
14.7 °C at Pearce RAAF
Warmest nights on average 18.1 °C at Rottnest Island
Warmest night 24.0 °C at Mandurah on the 20th
Warmest on average overall 23.9 °C at Pearce RAAF
Coolest on average overall 21.3 °C at Garden Island HSF
Wettest overall 23.6 mm at Karnet
Driest overall 1.0 mm at Garden Island HSF
Wettest day 20.1 mm at Karnet on the 24th
Strongest wind gust 83 km/h at Rottnest Island on the 22nd

Record lowest January daily maximum temperature
New record
(°C)
Old
record
Years of
record
Average for
January
Gosnells City 20.0 on the 23rd 20.3 on the 3rd in 2007 26 33.1



Record lowest January mean daily maximum temperature
New record
(°C)
Old
record
Years of
record
Average for
January
Swanbourne 27.6 27.8 in 2006 25 29.9



Record lowest January mean daily minimum temperature
New record
(°C)
Old
record
Years of
record
Average for
January
Perth Metro 16.6 = 16.6 in 2007 25 18.1

Lowest January mean daily minimum temperature for at least 20 years
Observed
(°C)
Most recent
lower
Average for
January
Pearce RAAF 14.7 14.3 in 1990 17.0



Record lowest January mean temperature
New record
(°C)
Old
record
Years of
record
Average for
January
Swanbourne 22.3 = 22.3 in 2006 25 24.1



Summary statistics for January 2019
Maximum temperatures
(°C)
Minimum temperatures
(°C)
Rainfall
(millimetres)
Mean for
January
2019
Diff
from
average
Highest for
January
2019
Mean for
January
2019
Diff
from
average
Lowest for
January
2019
Total for
January
2019
Average
for
January
Rank of
January
2019
Fraction of
January
average
Bickley 29.7 -0.9 40.4 20th 14.7 -0.7 8.4 4th 13.8 20.8 average 66%
Garden Island HSF 24.6 -2.8 33.0 31st 18.0 -1.0 13.7 25th 1.0 15.6 average 6%
Jandakot Aero 30.1 -1.3 42.0 20th 15.0 -1.8 6.8 4th 4.0 16.5 average 24%
Mandurah 27.8 -1.7 35.5 19th 17.6 -1.4 13.2 25th 4.2 18.4 average 23%
Millendon (Swan Valley) 32.2   43.9 20th 15.0   8.5 4th 9.6
Pearce RAAF 33.1 -0.4 44.4 20th 14.7 -2.3 10.0 12th 3.8 10.6 average 36%
Perth Airport 31.3 -0.5 42.9 20th 15.8 -1.3 7.0 4th 6.2 11.1 average 56%
Perth Metro 30.5 -0.7 42.1 20th 16.6 -1.5 10.0 4th 7.2 19.7 average 37%
Rottnest Island 24.9 -1.6 35.4 20th 18.1 -1.0 14.1 25th 4.8 16.6 average 29%
Swanbourne 27.6 -2.3 37.7 20th 17.1 -1.2 11.3 25th 5.0 20.3 average 25%

Daily maximum temperatures for January 2019
12345678910111213141516171819202122232425262728293031
Bickley33.422.421.223.830.934.433.330.931.125.428.534.829.329.929.527.425.731.938.240.432.227.718.617.325.629.633.838.030.930.134.2
Garden Island HSF25.323.121.023.127.129.925.328.025.522.223.824.522.722.822.922.022.226.427.729.422.927.220.620.021.024.425.725.623.324.533.0
Gosnells City33.225.033.436.534.032.831.528.936.029.530.330.028.027.034.039.642.020.021.026.933.236.432.033.0
Jandakot Aero32.023.923.424.031.834.931.930.125.226.633.627.728.729.127.326.033.338.842.029.330.222.320.925.332.634.839.631.130.436.1
Karnet33.021.521.023.930.834.533.828.531.525.829.830.028.726.825.832.040.019.819.034.036.830.529.233.6
Mandurah28.723.222.422.628.433.630.430.427.223.424.330.026.226.926.324.523.828.135.534.026.931.120.020.623.929.931.135.027.829.235.2
Millendon (Swan Valley)35.326.024.925.834.037.234.734.033.827.530.135.429.732.131.930.128.234.341.043.932.830.221.920.427.632.937.041.032.732.937.4
Pearce RAAF36.127.725.526.634.537.735.834.834.828.431.137.230.933.132.330.329.035.041.944.433.630.623.821.129.033.737.742.834.133.737.5
Perth Airport34.124.624.525.532.736.732.533.931.526.128.235.428.730.230.529.226.734.040.542.931.630.621.520.426.732.936.840.231.733.237.3
Perth Metro32.523.823.824.232.536.432.233.131.225.527.533.727.728.829.128.126.032.840.442.129.830.522.220.625.732.035.539.630.630.936.2
Rottnest Island26.923.922.422.125.027.325.025.424.823.823.225.324.324.123.622.823.125.729.235.423.824.920.721.422.224.125.327.824.123.729.5
Swanbourne26.823.022.723.629.334.326.431.428.826.127.124.724.724.924.224.229.037.037.725.027.222.421.423.027.731.934.625.827.434.9
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 January 2019
12345678910111213141516171819202122232425262728293031
Bickley16.916.213.58.412.917.117.214.914.817.012.914.816.415.513.213.412.512.915.921.521.516.512.512.08.612.013.517.316.613.813.2
Garden Island HSF19.919.218.214.316.320.419.818.018.719.815.318.319.620.016.817.617.217.019.122.320.619.016.615.813.715.317.318.018.316.418.0
Gosnells City17.820.09.920.816.019.016.114.018.919.515.015.515.515.020.014.511.016.018.116.613.117.8
Jandakot Aero16.419.616.86.812.317.716.717.618.113.911.211.917.417.115.514.814.011.615.319.617.617.116.014.59.114.016.112.412.215.517.2
Karnet16.614.07.012.515.616.214.615.610.516.713.413.812.212.515.918.216.912.28.816.114.912.514.0
Mandurah20.319.617.713.815.419.419.417.618.619.416.317.419.018.816.716.316.516.220.124.020.718.916.015.113.214.016.818.316.715.717.6
Millendon (Swan Valley)14.920.115.58.510.518.715.118.618.212.911.611.416.418.014.313.413.414.515.818.417.718.315.214.710.914.116.311.210.917.117.1
Pearce RAAF12.719.715.810.211.019.514.918.719.213.211.610.016.916.912.913.213.513.715.917.916.717.314.014.110.013.617.511.410.816.617.4
Perth Airport16.320.016.97.014.818.617.218.418.513.211.712.018.917.516.214.514.816.016.120.717.618.815.514.612.415.617.411.611.017.417.1
Perth Metro17.219.717.410.012.920.319.718.318.517.014.514.020.117.717.116.516.014.218.220.019.919.716.015.011.615.216.113.214.017.3
Rottnest Island19.218.917.515.817.119.520.018.619.218.718.318.718.919.017.517.617.817.519.721.819.619.414.714.514.116.018.218.918.217.718.8
Swanbourne17.719.317.312.214.819.819.317.818.318.416.015.819.417.616.216.116.215.018.521.820.519.015.715.211.315.117.116.916.816.818.0
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 January 2019
12345678910111213141516171819202122232425262728293031
Anketell - - 1.2 - - - - - - - - - - - - - - - - - - - 1.0 8.2 0.6 - - - - - -
Bickley - - 1.2 - - - - - - - - - - - - - - - - - - - 2.8 9.6 0.2 - - - - - -
Bungendore - - 2.8 - - - - - 0.4 - - - - - - - - - - - - - 1.0 8.8 0.6 - - - - - -
Chidlow - - 0.2 - - - - - 1.2 - - - - - - - - - - - - - - 5.6






Garden Island HSF - - - - - - - - - - - - - - - - - - - - - - - 0.6 0.4 - - - - - -
Gidgegannup - - 0.8 - - - - - 0.2 - - - - - - - - - - - - - 0.8 10.6 0.2 - - - - - -
Gosnells City - - - - - - - - - - - - - - - - - - - - - 4.6 - - - - - - -
Huntly - 0.2 3.0 - - - - - - - - - - - - - - - - - - - 6.6 9.5 - - - - - - -
Jandakot Aero - - 0.6 - - - - -
- - - - - - - - - - - - - - 3.2 0.2 - - - - - -
Jarrahdale - - 2.0 - - - - - - - - 0.2 - - - - - - - - - - 2.4 14.0 0.6 - - - - - -
Karnet 0.5 1.4 - - - - - - - - - - - - - - - - - - 1.2 20.1 0.4

- - - -
Karragullen North - - 1.4 - - - - - 1.0 - - - - - - - - - - - - - 3.8 11.8 0.2





Maida Vale - - 0.8 - - - - - - - - - - - - - - - - - - - 1.0 7.0






Mandurah - - 0.2 0.2 - - - - - - - - - - - - - - - - - - 0.6 3.2 - - - - - - -
Midland - - 1.0 - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Millendon (Swan Valley) - - 0.6 - - - - - 0.2 - - - - - - - - - - - - - 3.8 4.8 0.2 - - - - - -
Mosman Park - - 1.6 - - - - - 0.6





















Mount Solus - 0.2 1.0 - - - - - - - - - - - - - - - - - - - 1.0 16.6 - - - - - - -
Muchea - - 1.2 - - - - - - - - - - - - - - - - - - - - 2.8 - - - - - - -
Mundaring - - 1.0 - - - - - - - - - - - - - - - - - - 0.1 1.2 9.0 0.4





Noble Falls

0.6



























Pearce RAAF - - 0.6 - - - - - - - - - - - - - - - - - - - - 3.2 - - - - - - -
Perth Airport - - 0.6 - - - - - - - - - - - - - - - - - - - 0.4 5.0 0.2 - - - - - -
Perth Metro - - 1.8 - - - - - - - - - - - - - - - - - - - 0.4 4.8 0.2 - - - - -
Pinjarra South - - 0.6 - - - - - - - - - - - - - - - - - - - 2.2 2.6 - - - - - - -
Roleystone - - - - - - - - 1.6 - - - - - - - - - - - - - 2.2 8.0






Rottnest Island - - 0.8 - - - - - 0.8 - - - - - - - - - - - - - 1.2 2.0 - - - - - - -
Serpentine - - 0.8 0.2 - - - - - - - - - - - - - - - - - - 0.2 5.0 0.6 - - - - - -
Swanbourne - - 1.6 - - - - - 0.6 -
- - - - - - - - - - - 0.4 2.4 - - - - - - -
Tamala Park (Mindarie) - - - - - - - 0.4 - - - - - - - - - - - - - - 1.8 1.8 - - - - - - -
Wanneroo - - - - - - - - 0.1 - - - - - - - - - - - - - 6.6 1.8






Werribee - - - 0.2 - - - - - - - - - - - - - - - - - 0.2 - 3.6 - - - - - - -
Whiteman Park - - 1.0 - - - - - - - - - - - - - - - - - - - 0.6 5.2






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, 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 10 am on Friday 1 February 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