Greater Perth in spring 2017: Mild spring temperatures; near average rainfall

Both daytime and overnight temperatures were above average across the Greater Perth in spring 2017. Rainfall in spring 2017 was near average to below average.

Near average to below average rainfall

  • Spring rainfall was near average to below average, due to near average rainfall in September and October compensating for a dry November
  • Spring total rainfall was generally in the 110 mm to 140 mm on the coastal plain, but over 200 mm in the hills

Mild daytime and overnight temperatures

  • Mean maximum temperatures for spring were generally 0.5 °C to 1.5 °C above average across the Greater Perth region
  • Mean minimum temperatures for spring were generally 0.5 °C to 1.5 °C above average for coastal plain sites

Perth Metro

  • Spring rainfall was 124.2 mm, which was below average but wettest spring for 3 years, since 137.8 mm was recorded in spring 2014
  • Perth Metro recorded 35 rain days in spring, the highest for eight years, since 37 rain days were recorded in spring 2009
  • Mean maximum temperature was 24.4 °C, which was the equal third-warmest spring, equal with spring 2013 at Perth Metro in 119 years of record; top two springs were 25.9 °C in 2015 and 25.3 °C in 2010
  • Mean minimum temperature was 12.7 °C, 0.9 °C above average

Further information

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Extremes in spring 2017
Hottest day 38.0 °C at Perth Airport on 11 Nov
Warmest days on average 25.1 °C at Millendon (Swan Valley)
Coolest days on average 21.5 °C at Rottnest Island
21.8 °C at Bickley
Coldest day 12.3 °C at Bickley on 7 Oct
Coldest night 2.7 °C at Jandakot Aero on 27 Sep
Coolest nights on average 10.5 °C at Bickley
Warmest nights on average 14.6 °C at Rottnest Island
14.0 °C at Mandurah
Warmest night 23.5 °C at Gosnells City on 12 Nov
Warmest on average overall 18.5 °C at Perth Metro
Coolest on average overall 16.1 °C at Bickley
Wettest overall 227.7 mm at Huntly
Driest overall 83.4 mm at Mandurah
Wettest day 44.2 mm at Huntly on 22 Sep
Strongest wind gust 100 km/h at Ocean Reef on 16 Oct




Summary statistics for spring 2017
Maximum temperatures
(°C)
Minimum temperatures
(°C)
Rainfall
(millimetres)
Mean for
spring
2017
Diff
from
average
Highest for
spring
2017
Mean for
spring
2017
Diff
from
average
Lowest for
spring
2017
Total for
spring
2017
Average
for
spring
Rank of
spring
2017
Fraction of
spring
average
Bickley 21.8 +0.6 35.5 11 Nov 10.5 +0.6 3.5 2 Sep 214.4 232.1 average 92%
Jandakot Aero 24.2 +1.1 36.5 16 Nov 11.6 +1.4 2.7 27 Sep 141.6 162.6 average 87%
Mandurah 22.8 +0.9 33.1 6 Nov 14.0 +0.4 6.9 2 Sep 83.4 122.6 low 68%
Medina Research Centre     36.9 16 Nov 11.9 +0.9 2.7 15 Sep
Millendon (Swan Valley) 25.1   37.8 11 Nov 11.5   3.3 29 Sep 129.4
Pearce RAAF 25.0 +1.4 37.7 11 Nov 11.6 +1.1 2.9 29 Sep 116.0 127.7 average 91%
Perth Airport 24.7 +1.7 38.0 11 Nov 11.9 +1.3 3.4 4 Sep 109.0 142.4 low 77%
Perth Metro 24.4 +1.0 36.9 11 Nov 12.7 +0.9 4.2 4 Sep 124.2 155.0 low 80%
Rottnest Island 21.5 +0.7 33.9 7 Nov 14.6 +0.3 9.1 24 Sep 116.2 104.2 average 112%
Swanbourne 23.0 +0.5 35.5 7 Nov 13.6 +0.9 6.8 2 Sep 131.2 150.2 average 87%
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 Seasonal 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.

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 10 am on Friday 1 December 2017. 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