Thursday, 9 January 2020 - Annual Climate Summary for Greater Perth - Product code IDCKGC51L0

Greater Perth in 2019: a dry and warm year

2019 was a very dry and warm year for Greater Perth. Annual rainfall totals were below average and the lowest since 2010, largely due to a dry autumn and spring. Annual mean maximum temperatures were above average, and Perth Metro had one of its warmest years on record.

Dry autumn and spring

  • Annual rainfall totals ranged from 500 to 650 mm for most sites, and up to 900 to 950 mm along the Perth hills
  • It was Perth Metro's third-driest year and driest since 2010 in 26 years of record (the annual rainfall in 2019 was estimated at 590.2 mm)
  • Perth Airport recorded 524.6 mm in 2019, which was its fourth-driest year on record and driest since 2010 (records commenced in 1944)
  • The wettest day was 23 June with daily rainfall generally between 40 mm and 70 mm

Above average daytime temperatures, near average overnight temperatures

  • Annual mean maximum temperature were above average, and by nearly two degrees at Perth Airport and Pearce RAAF
  • Perth Metro's mean maximum temperature was 25.7 °C, which was 1.0 °C above average, and equalled the records of 2011 and 2012
  • Perth Airport, Pearce RAAF and Bickley either exceeded or equalled their previous record for highest annual mean maximum temperature
  • The hottest day in 2019 was on 20 January for most sites; Pearce RAAF recorded the highest temperature at 44.4 °C
  • Perth Metro recorded a total of seven days with temperature at 40 °C or above in 2019, the highest number of 40 °C days since 2012 (8 days)
  • During the first half of December, Perth Metro and Perth Airport not only recorded their first run of three consecutive days of over 40 °C (between the 13th and 15th) in December, but also doubled their previous record count of 40 °C days with four and eight respectively
  • The annual mean minimum temperatures were near average
  • The coldest mornings in 2019 were during the mid-May for Greater Perth; Perth Airport had a run of two frosty mornings with 1.7 °C (17th) and 1.5 °C (18th), and the last time was 51 years ago in 1968 (1.8 °C and 1.6 °C on 25 and 26 May)
  • Pearce RAAF and Jandakot Aero were only two locations with sub-zero temperatures at -0.3 °C (18 May) and -0.1 °C (19 May) respectively

Perth Metro

  • Annual rainfall total was estimated at 590.2 mm ( a rain gauge blockage on 5 October means the exact total is unknown)
  • The mean daily maximum temperature for Perth Metro was 25.7 °C, which is 1.0 °C above the long-term average of 24.7 °C. The warmest day was 42.1 °C on 20 Jan, and the coolest day was on 5 Jul when the temperature reached 13.5 °C
  • The mean daily minimum temperature for Perth Metro was 12.8 °C, equal to the long-term average.. The coldest morning was 1.6 °C on 19 May, and the warmest morning was on 6 Dec when the minimum temperature was 24.6 °C

Further information

Media
(03) 9669 4057
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Extremes Maps Records Summaries Important notes the top

Extremes in 2019
Hottest day 44.4 °C at Pearce RAAF on 20 Jan
Warmest days on average 27.0 °C at Pearce RAAF
Coolest days on average 22.6 °C at Rottnest Island
Coldest day 10.4 °C at Bickley on 5 Jul
Coldest night -0.3 °C at Pearce RAAF on 18 May
Coolest nights on average 11.4 °C at Bickley
Warmest nights on average 15.8 °C at Rottnest Island
Warmest night 27.1 °C at Pearce RAAF on 6 Dec
Warmest on average overall 19.6 °C at Pearce RAAF
Coolest on average overall 17.4 °C at Bickley
Wettest overall 957.4 mm at Bickley
Driest overall 466.8 mm at Rottnest Island
Wettest day 77.2 mm at Bungendore on 23 Jun
Strongest wind gust 107 km/h at Ocean Reef on 16 Aug
107 km/h at Rottnest Island on 4 Oct

Extremes Maps Records Summaries Important notes the top

Record highest annual mean daily maximum temperature
New record
(°C)		 Old
record		 Years of
record		 Annual
average
Perth Airport 26.2 26.1 in 2011 74 24.5
Pearce RAAF 27.0 26.8 in 2015 55 25.2
Bickley 23.4 = 23.4 in 2010 25 22.6
Perth Metro 25.7 = 25.7 in 2011 25 24.7


Extremes Maps Records Summaries Important notes the top

Summary statistics for 2019
Maximum temperatures
(°C)		 Minimum temperatures
(°C)		 Rainfall
(millimetres)
Mean
for
2019		 Diff
from
average		 Highest
for
2019		 Mean
for
2019		 Diff
from
average		 Lowest
for
2019		 Total
for
2019		 Average
annual
total		 Rank
of
2019		 Fraction
of annual
average
Bickley 23.4 +0.8 40.4 20 Jan 11.4 +0.1 2.4 5 Sep 957.4 1080.4 low 89%
Garden Island HSF 22.8 +0.1 38.3 13 Dec 15.0 0.0 7.1 18 Jun 506.2 598.0 low 85%
Jandakot Aero 25.5 +0.9 42.0 20 Jan 11.8 +0.3 -0.1 19 May 638.0 819.6 v low 78%
Mandurah 23.7 +0.4 39.5 12 Dec 14.7 -0.1 5.4 5 Sep 517.0 656.7 low 79%
Millendon (Swan Valley) 26.5   43.9 20 Jan 11.9   0.5 18 May 526.8
Pearce RAAF 27.0 +1.8 44.4 20 Jan 12.1 -0.1 -0.3 18 May 502.4 652.1 low 77%
Perth Airport 26.2 +1.7 42.9 20 Jan 12.3 +0.1 1.5 18 May 524.6 762.1 v low 69%
Perth Metro 25.7 +1.0 42.1 20 Jan 12.8 0.0 1.6 19 May
Rottnest Island 22.6 +0.4 37.9 13 Dec 15.8 +0.1 8.5 28 Jun 466.8 568.7 low 82%
Swanbourne 24.1 0.0 40.0 9 Nov 14.3 +0.3 4.6 19 Jun 595.4 728.2 v low 82%

Extremes Maps Records Summaries Important notes the top

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.”

This statement has been prepared based on information available at 10 am on Tuesday 7 January 2020. 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