Greater Perth in 2017: Rain and temperatures near average

Annual rainfall in 2017 was near average across the Greater Perth region, with a wet start to the year and a wet finish, but a dry April to June period. Annual mean maximum and minimum temperatures were both close to average for most locations.

Near average annual rainfall

  • Annual rainfall was near average with totals generally in the 600 mm to 850 mm range along the coastal plain, and over 1200 mm in the hills
  • The number of rain days ranged from 110 to 120 for the coastal plain, up to 140 in the hills
  • A cloudband associated with a tropical low brought heavy rainfall to the Perth region in early February, with several sites reporting their highest daily rainfall on record on the 10th
  • Perth Metro recorded 114.4 mm in the 24 hours to 9am on 10 February, its second-highest daily rainfall in 142 years of record, only behind 120.6 mm on 9 February 1992

Near average daytime and overnight temperatures

  • Annual mean maximum and minimum temperatures were near average across most of Greater Perth
  • The hottest day of 2017 was 4 January when Pearce RAAF recorded a daily maximum temperature of 44.5 °C
  • The coldest day was 5 July when the daily maximum temperature at Bickley only reached 10.0 °C
  • The coldest morning was 2 August, when Jandakot recorded a daily minimum temperature of 0.7 °C

Perth Metro

  • Annual rainfall in 2017 was 854.0 mm, the wettest for six years, since 860.8 mm was recorded in 2011
  • Rain fell on 117 days, compared to the average of 108 days, and was the highest for nine years, since 117 rain days were also recorded in 2008
  • Perth Metro recorded 73 rain days between July and October, its highest number of rain days for the July to October period for 62 years, since 1955 when 81 rain days were recorded. The average number of rain days for the July to October period is 56
  • The annual mean maximum temperature at Perth Metro was 25.0 °C, which was 0.3 °C above average
  • Perth Metro recorded a total of 3 days with temperatures at 40 °C or higher in 2017, which is close to the long-term average; the hottest day was 42.0 °C on 26 January
  • Perth Metro recorded a total of 12 days with temperatures at 37 °C or higher in 2017, which was slightly below the long-term average and the lowest number for 11 years, since 9 days at or above 37 °C were recorded in 2006
  • The annual mean minimum temperature at Perth Metro was 13.1 °C, which was 0.3 °C above average

Further information

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Extremes in 2017
Hottest day 44.5 °C at Pearce RAAF on 4 Jan
Warmest days on average 26.0 °C at Pearce RAAF
Coolest days on average 22.2 °C at Rottnest Island
Coldest day 10.0 °C at Bickley on 5 Jul
Coldest night 0.7 °C at Jandakot Aero on 2 Aug
Coolest nights on average 11.4 °C at Bickley
Warmest nights on average 15.7 °C at Rottnest Island
14.8 °C at Mandurah
Warmest night 25.9 °C at Gosnells City on 25 Feb
Warmest on average overall 19.1 °C at Mandurah
19.1 °C at Pearce RAAF
Coolest on average overall 16.9 °C at Bickley
Wettest overall 1386.5 mm at Huntly
Driest overall 619.8 mm at Mandurah
Wettest day 128.0 mm at Huntly on 10 Feb
Strongest wind gust 102 km/h at Garden Island HSF on 28 Jul

Record highest daily rainfall
New record
(mm)
Old
record
Years of
record
Rottnest Island 93.8 on 10 Feb 66.8 on 21 Jul 2011 30
Huntly 128.0 on 10 Feb 101.5 on 16 Apr 2007 28
Swanbourne 97.4 on 10 Feb 82.0 on 4 Aug 1994 25
Cloon 108.6 on 10 Feb 79.6 on 19 May 2005 24



Summary statistics for 2017
Maximum temperatures
(°C)
Minimum temperatures
(°C)
Rainfall
(millimetres)
Mean
for
2017
Diff
from
average
Highest
for
2017
Mean
for
2017
Diff
from
average
Lowest
for
2017
Total
for
2017
Average
annual
total
Rank
of
2017
Fraction
of annual
average
Bickley 22.4 -0.2 41.0 4 Jan 11.4 +0.1 3.4 1 Aug 1174.4 1078.9 average 109%
Jandakot Aero 24.8 +0.2 41.7 26 Jan 12.2 +0.8 0.7 2 Aug 830.6 823.7 average 101%
Mandurah 23.4 +0.1 37.6 4 Mar 14.8 0.0 5.7 2 Aug 619.8 667.3 average 93%
Pearce RAAF 26.0 +0.8 44.5 4 Jan 12.2 0.0 1.5 26 Jun 725.6 654.6 high 111%
Perth Airport 25.3 +0.8 43.3 4 Jan 12.6 +0.4 1.0 2 Aug 729.8 765.6 average 95%
Perth Metro 25.0 +0.3 42.0 26 Jan 13.1 +0.3 1.7 2 Aug 854.0 844.0 average 101%
Rottnest Island 22.2 0.0 39.3 26 Jan 15.7 0.0 8.2 1 Aug        
Swanbourne 23.7 -0.4 40.1 26 Jan 14.3 +0.4 5.1 2 Aug 807.6 730.2 average 111%
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.

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.

In September 2017 this summary was broadened to include 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 Tuesday 9 January 2018. 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
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