Greater Perth in winter 2017: Above average winter days and nights

Both daytime and overnight temperatures were above average across the Greater Perth region. Rainfall in winter 2017 was near average for most sites due to a wet July and August partly compensating for a very dry June.

This summary includes data from observing sites in or near the Greater Perth “Greater Capital City Statistical Area” (GCCSA) – see the notes.

Near average rainfall

  • Rainfall totals were between 320 mm and 420 mm for coastal plain sites, increasing to 600 mm-700 mm in the hills
  • June rainfall was less than half of average, whilst July and August rainfall was above average

Above average mean maximum and minimum temperatures

Perth Metro

  • Winter rainfall was 412.2 mm, which was about 60 mm below average, but the wettest winter for six years, since 447.6 mm was recorded in 2011
  • Mean maximum temperature was 19.5 °C, which was 0.6 °C above average
  • Warmest day was 25.6 °C on 5 June, which was the warmest winter day for two years, since 27.0°C was recorded on 16 August 2015
  • Mean minimum temperature was 9.2 °C, which was 1 °C above average
  • Coldest and mildest nights this winter occurred within 12 days in August: lowest temperature of 1.7 °C on the 2nd, and highest minimum of 15.1 °C on the 14th

Further information

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Extremes in winter 2017
Hottest day 26.7 °C at Medina Research Centre on 5 Jun
Warmest days on average 19.9 °C at Medina Research Centre
Coolest days on average 16.0 °C at Bickley
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 8.2 °C at Bickley
Warmest nights on average 13.2 °C at Rottnest Island
11.7 °C at Mandurah
Warmest night 18.0 °C at Rottnest Island on 3 Jun
Warmest on average overall 16.0 °C at Rottnest Island
15.1 °C at Swanbourne
Coolest on average overall 12.1 °C at Bickley
Wettest overall 733.5 mm at Huntly
Driest overall 321.4 mm at Garden Island HSF
Wettest day 71.0 mm at Huntly on 9 Aug
Strongest wind gust 102 km/h at Garden Island HSF on 28 Jul


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




Record highest winter daily minimum temperature
New record
(°C)
Old
record
Years of
record
Average for
winter
Rottnest Island 18.0 on 3 Jun = 18.0 on 26 Aug 1994 30 12.7



Highest winter mean daily minimum temperature for at least 20 years
Observed
(°C)
Most recent
higher
Average for
winter
Jandakot Aero 8.6 8.7 in 1996 7.1



Highest winter mean temperature for at least 20 years
Observed
(°C)
Most recent
higher
Average for
winter
Jandakot Aero 13.9 14.0 in 1991* 12.8

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




Summary statistics for winter 2017
Maximum temperatures
(°C)
Minimum temperatures
(°C)
Rainfall
(millimetres)
Mean for
winter
2017
Diff
from
average
Highest for
winter
2017
Mean for
winter
2017
Diff
from
average
Lowest for
winter
2017
Total for
winter
2017
Average
for
winter
Rank of
winter
2017
Fraction of
winter
average
Bickley 16.0 +0.3 22.0 28 Aug 8.2 +0.6 3.4 1 Aug 599.8 585.5 average 102%
Garden Island HSF 18.7 +0.4 24.4 27 Aug 12.1 +0.6 4.8 3 Aug 321.4 313.7 average 102%
Gosnells City 19.7 +0.4 26.1 5 Jun     3.4 1 Aug 410.2 451.2 average 91%
Jandakot Aero 19.2 +0.6 25.2 28 Aug 8.6 +1.5 0.7 2 Aug 413.8 453.5 average 91%
Mandurah 18.4 +0.3 25.7 27 Aug 11.7 +0.7 5.7 2 Aug 323.8 331.5 low 98%
Medina Research Centre 19.9 +1.0 26.7 5 Jun 9.3 +0.8 1.2 2 Aug 392.9 397.8 average 99%
Millendon (Swan Valley) 19.5   25.4 13 Jun 8.5   1.4 2 Aug 347.8
Pearce RAAF 19.7 +1.3 26.4 5 Jun 8.9 +0.3 1.5 26 Jun 338.8 368.3 average 92%
Perth Airport 19.5 +1.0 25.3 5 Jun 9.1 +0.8 1.0 2 Aug 379.4 429.7 average 88%
Perth Metro 19.5 +0.6 25.6 5 Jun 9.2 +1.0 1.7 2 Aug 412.2 474.2 low 87%
Rottnest Island 18.7 +0.6 23.5 6 Jun 13.2 +0.5 8.2 1 Aug   302.3    
Swanbourne 19.2 +0.3 25.4 5 Jun 11.0 +0.9 5.1 2 Aug 387.0 389.3 average 99%
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 September 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
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