Greater Perth in 2018: near average temperature and rainfall

Rainfall in 2018 was near average across Greater Perth, and annual mean maximum and minimum temperatures were generally close to average.

The Australian annual climate statement provides a comprehensive summary of Australia's climate during 2018. Information about changes and long-term trends in Australia's climate can be found in State of the Climate 2018.

Average rainfall

  • Annual rainfall ranged from 600-800 mm for most sites, to over 1200 mm in the Perth hills
  • A cloudband associated with ex-tropical cyclone Joyce brought heavy falls between 50 to 150 mm in the 24 hours to 9am on 16 January with many annual daily rainfall records registered
  • Perth Metro daily rainfall of 96.2 mm on 16 January was its second-highest January daily rainfall on record; the highest being 104.0 mm on 22 January 2000
  • August was a very wet month across Greater Perth; Perth Metro's monthly rainfall was 186.0 mm, the wettest August on record (the previous record of 175.6 mm set in 2004)

Near average temperatures

  • Both annual mean maximum and minimum temperatures were close to average for most sites in Greater Perth
  • Perth Metro recorded a maximum of 41.2  °C on 22 December, which was its only 40 °C day in 2018, and its highest temperature for 13 months (a maximum of 42.0 °C was recorded on 26 January 2017)

Perth Metro

  • Perth Metro recorded an annual total of 741.6 mm, which is near average but drier than 2017 (854.0 mm)
  • The mean daily maximum temperature for Perth Metro was 24.7 °C, which is 0.1 °C below the long-term average of 24.8 °C
  • The warmest day was 41.2 °C on 22 December, and the coolest day was on 7 June when the temperature reached 14.1 °C
  • The mean daily minimum temperature for Perth Metro was 13.0 °C, which is 0.2 °C above the long-term average of 12.8 °C
  • The coldest morning was 2.8 °C on 11 August, and the warmest morning was on 6 March when the minimum temperature was 25.5 °C

Further information

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Extremes in 2018
Hottest day 42.1 °C at Pearce RAAF on 22 Dec
Warmest days on average 25.8 °C at Pearce RAAF
Coolest days on average 21.9 °C at Rottnest Island
22.2 °C at Bickley
Coldest day 10.1 °C at Bickley on 29 Aug
Coldest night 1.0 °C at Karnet on 11 Aug
Coolest nights on average 11.2 °C at Bickley
Warmest nights on average 15.7 °C at Rottnest Island
14.6 °C at Mandurah
Warmest night 26.0 °C at Millendon (Swan Valley) on 6 Mar
26.0 °C at Pearce RAAF on 6 Mar
Warmest on average overall 19.0 °C at Pearce RAAF
Coolest on average overall 16.7 °C at Bickley
Wettest overall 1345.4 mm at Karnet
Driest overall 592.6 mm at Rottnest Island
Wettest day 147.6 mm at Karragullen on 16 Jan
Strongest wind gust 130 km/h at Garden Island HSF on 25 Feb

Record highest daily rainfall
New record
(mm)
Old
record
Years of
record
Wanneroo 94.6 on 16 Jan 92.0 on 29 Jul 1987 81
Gidgegannup 114.2 on 16 Jan 113.5 on 29 Jan 1990 61
Karragullen North 138.6 on 16 Jan 111.0 on 30 Jul 2001 52
Roleystone 139.2 on 16 Jan 135.4 on 9 Feb 1992 52
Subiaco Treatment Plant 132.4 on 16 Jan 98.0 on 29 Jul 1987 52
Bickley 139.2 on 16 Jan 137.0 on 30 Jul 2001 50
Karragullen 147.6 on 16 Jan 141.0 on 29 Jul 1987 47
Pickering Brook 131.4 on 16 Jan 126.4 on 30 Jul 2001 43
Fremantle 128.4 on 16 Jan 87.0 on 29 Jul 1987 32
Pickering Brook North 134.6 on 16 Jan 115.0 on 30 Jul 2001 31
Rottnest Island 142.2 on 16 Jan 93.8 on 10 Feb 2017 31
Huntly 144.0 on 16 Jan 128.0 on 10 Feb 2017 29
Swanbourne 138.6 on 16 Jan 97.4 on 10 Feb 2017 26



Highest annual total rainfall for at least 20 years
Observed
(mm)
Most recent
higher
Annual
average
Karnet 1345.4 1509.8 in 1991* 1163.2
Bickley 1273.6 1410.3 in 1996 1083.0

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





Summary statistics for 2018
Maximum temperatures
(°C)
Minimum temperatures
(°C)
Rainfall
(millimetres)
Mean
for
2018
Diff
from
average
Highest
for
2018
Mean
for
2018
Diff
from
average
Lowest
for
2018
Total
for
2018
Average
annual
total
Rank
of
2018
Fraction
of annual
average
Bickley 22.2 -0.4 37.9 22 Dec 11.2 -0.1 1.4 15 Sep 1273.6 1083.0 high 118%
Garden Island HSF 22.1 -0.6 40.1 14 Jan 15.0 0.0 5.6 19 Aug 635.6 603.4 average 105%
Jandakot Aero 24.5 -0.1 40.5 22 Dec 12.0 +0.5 1.4 12 Aug 844.0 824.2 average 102%
Mandurah 23.0 -0.3 40.3 14 Jan 14.6 -0.2 5.7 10 Aug 659.0 666.7 average 99%
Millendon (Swan Valley) 25.5   41.3 22 Dec 12.0   1.6 16 Sep 648.6
Pearce RAAF 25.8 +0.6 42.1 22 Dec 12.2 0.0 2.5 16 Sep 682.2 655.1 average 104%
Perth Airport 25.1 +0.6 40.9 22 Dec 12.5 +0.3 2.5 10 Aug 737.2 765.2 average 96%
Perth Metro 24.7 -0.1 41.2 22 Dec 13.0 +0.2 2.8 11 Aug 741.6 733.2 average 101%
Rottnest Island 21.9 -0.3 37.9 22 Dec 15.7 0.0 6.8 10 Aug 592.6 573.3 average 103%
Swanbourne 23.3 -0.8 39.0 22 Dec 14.1 +0.2 5.2 11 Aug 817.4 734.0 high 111%

Notes

The Annual climate summary, generally published on the second working day of the year, 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.

The Australian annual climate statement provides a comprehensive summary of Australia's climate during 2018. Information about changes and long-term trends in Australia's climate can be found in State of the Climate 2018.

This statement has been prepared based on information available at 3 pm on Thursday 3 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