Greater Perth in May 2019: very dry, below average night-time temperatures

Rainfall in May 2019 was well below average, and it was driest May on record for Perth Metro and Perth Airport. The last time the city saw a drier May was 55 years ago in 1964. Mean minimum temperatures were well below average across Greater Perth, and coolest May on record for Perth Metro. Mean maximum temperatures were generally below average except for Perth Airport and Pearce RAAF.

Very dry across Perth

  • May rainfall was well below average across Greater Perth; monthly totals were generally 10-20 mm, to 30-40 mm in the Perth hills
  • May 2019 was either driest May on record for Perth Airport and several sites, or driest May rainfall since 1964 at sites with over 60 years of rainfall observations in the Perth hills
  • Perth Metro recorded 17.8 mm, which was its driest May on record, and previous record was 26.4 mm in May 2000
  • For the Perth city, 17.8 mm recorded at Perth Metro (Mount Lawley) was the second-driest May on record with rainfall observations commenced in 1876, and driest May for 55 years, when 14.1 mm was recorded at Perth Regional Office in May 1964

Below average daytime and nighttime temperatures

  • Mean minimum temperatures were 1-3 °C below average across Greater Perth
  • Perth Metro recorded a mean minimum temperature of 8.7 °C, which was its coolest May on record, the previous record was 8.8 °C in May 2000
  • Perth Airport had its coolest May for 51 years, and Bickley and Swanbourne had their coolest May on record in terms of minimum temperatures
  • Mean maximum temperatures were slightly cooler than average for most sites, apart from Perth Airport and Pearce RAAF with mean maximum above average
  • Warm days with daily maximum temperatures in the high-20s to low-30s were on the 3rd, 14th and 15th for most sites; the highest temperature was 31.0 °C on the 15th at Pearce RAAF
  • Very low daily minimum temperatures of 5 °C or below were observed from the 17th to 19th for most sites; Swanbourne had its lowest May temperature on record on the 18th, while temperatures at Pearce RAAF and Jandakot Aero dropped below freezing level

Perth Metro

  • Total rainfall for Perth Metro was 17.8 mm, which is 21% of the long-term average of 86.8 mm
  • The mean daily maximum temperature for Perth Metro was 22.2 °C, which is 0.1 °C below the long-term average of 22.3 °C. The warmest day was 28.0 °C on the 14th, and the coolest day was on the 17th when the temperature reached 16.7 °C
  • The mean daily minimum temperature for Perth Metro was 8.7 °C, which is 1.8 °C below the long-term average of 10.5 °C. The coldest morning was 1.6 °C on the 19th, and the warmest morning was on the 6th when the minimum temperature was 16.2 °C

Further information

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Extremes in May 2019
Hottest day 31.0 °C at Pearce RAAF on the 15th
Warmest days on average 23.1 °C at Pearce RAAF
Coolest days on average 19.1 °C at Bickley
Coldest day 13.4 °C at Karnet on the 17th
Coldest night -0.3 °C at Pearce RAAF on the 18th
Coolest nights on average 7.5 °C at Jandakot Aero and at Pearce RAAF
Warmest nights on average 14.2 °C at Rottnest Island
Warmest night 18.1 °C at Rottnest Island on the 16th
Warmest on average overall 17.5 °C at Rottnest Island
Coolest on average overall 13.8 °C at Bickley
Wettest overall 39.2 mm at Mount Solus
Driest overall 12.2 mm at Perth Airport and at Werribee
Wettest day 16.0 mm at Bickley on the 6th
Strongest wind gust 80 km/h at Rottnest Island on the 16th

Record lowest May total rainfall

New record
(mm)
Old
record
Years of
record
Average for
May
Perth Airport 12.2 15.0 in 1964 76 97.4
Wanneroo 18.4 22.5 in 1972 72 107.9
Gidgegannup 20.0 27.4 in 1997 58 107.9
Karnet 26.2 36.7 in 2000 55 140.3
Roleystone 23.2 41.0 in 2006 52 120.5
Bickley 28.0 47.0 in 1983 51 129.8
Jandakot Aero 24.4 33.6 in 1983 45 104.8
Maida Vale 15.6 26.2 in 1983 37 99.6
Perth Metro 17.8 26.4 in 2000 27 86.8
Rottnest Island 12.4 17.6 in 2006 26 71.7
Swanbourne 15.2 22.0 in 2006 25 87.7

Lowest May total rainfall for at least 20 years

Observed
(mm)
Most recent
lower
Average for
May
Jarrahdale 36.2 35.2 in 1959* 152.5
Chidlow 15.0 11.7 in 1964 107.0
Pearce RAAF 18.0 4.2 in 1964 82.9
Mundaring 30.0 20.1 in 1964* 134.1
Karragullen North 28.4 16.7 in 1964* 126.9

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




Record lowest May temperature

New record
(°C)
Old
record
Years of
record
Average for
May
Swanbourne 4.8 on the 18th 5.0 on the 31st in 2013 26 12.6



Record lowest May mean daily minimum temperature

New record
(°C)
Old
record
Years of
record
Average for
May
Pearce RAAF 7.5 7.9 in 1968 58 10.7
Bickley 8.4 8.6 in 2006 25 10.2
Perth Metro 8.7 8.8 in 2000 25 10.5

Lowest May mean daily minimum temperature for at least 20 years

Observed
(°C)
Most recent
lower
Average for
May
Perth Airport 8.0 6.9 in 1968 10.4



Summary statistics for May 2019

Maximum temperatures
(°C)
Minimum temperatures
(°C)
Rainfall
(millimetres)
Mean for
May
2019
Diff
from
average
Highest for
May
2019
Mean for
May
2019
Diff
from
average
Lowest for
May
2019
Total for
May
2019
Average
for
May
Rank of
May
2019
Fraction of
May
average
Bickley 19.1 -0.2 25.9 15th 8.4 -1.8 3.5 19th 28.0 129.8 lowest 22%
Garden Island HSF 21.0 -0.4 26.0 3rd 12.1 -1.9 7.8 18th 22.0 72.5 v low 30%
Jandakot Aero 22.0 0.0 27.2 15th 7.5 -1.9 -0.1 19th 24.4 104.8 lowest 23%
Mandurah 20.5 -0.7 24.2 3rd 11.7 -1.8 6.5 18th 22.6 86.6 v low 26%
Millendon (Swan Valley) 22.8   30.2 15th 7.7   0.5 18th 16.0


Pearce RAAF 23.1 +1.1 31.0 15th 7.5 -3.2 -0.3 18th 18.0 82.9 v low 22%
Perth Airport 22.5 +0.7 29.7 15th 8.0 -2.4 1.5 18th 12.2 97.4 lowest 13%
Perth Metro 22.2 -0.1 28.0 14th 8.7 -1.8 1.6 19th 17.8 86.8 lowest 21%
Rottnest Island 20.8 -0.3 26.1 3rd 14.2 -1.1 9.8 18th 12.4 71.7 lowest 17%
Swanbourne 21.8 -0.4 28.0 3rd 11.1 -1.5 4.8 18th 15.2 87.7 lowest 17%

Daily maximum temperatures for May 2019

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
Bickley 14.1 16.7 23.4 20.6 19.3 16.7 18.6 19.7 19.0 20.5 21.3 22.0 20.0 24.7 25.9 15.6 13.6 15.2 17.7 17.9 17.9 18.8 18.5 18.6 18.8 18.2 18.4 19.6 19.7 20.3 22.3
Garden Island HSF 19.0 19.0 26.0 22.7 22.6 19.4 19.6 20.1 19.5 23.8 23.1 22.2 21.0 21.9 24.7 16.6 15.7 16.1 19.5 20.9 19.9 21.0 20.6 21.0 18.3 21.2 21.8 22.8 23.2 23.7 23.9
Gosnells City
20.1 27.0 24.0 22.5
21.3
23.0 25.0
24.5
28.5 28.3 17.6
18.4 23.0 20.5

22.1 21.5 21.1
22.3 22.5


Jandakot Aero 17.6 19.8 26.9 23.6 23.5 20.3 21.5 22.5 22.4 24.2 24.0 24.1 22.1 27.0 27.2 17.6 16.3 17.2 20.8 20.7 20.0 21.4 20.7 21.1 20.3 21.4 21.7 22.9 23.3 24.2 25.4
Karnet 14.8

21.1 21.1 17.5
19.8 19.9 21.9 22.0 22.0 19.4
25.1 15.5 13.4 14.9 18.0 17.8 18.0 19.0 19.3 19.6 18.5
18.8 20.6


Mandurah 17.5 19.1 24.2 22.1 21.7 19.9 20.3 21.6 21.4 21.3 22.1 21.6 21.5 21.1 22.4 16.1 15.9 16.5 18.5 19.6 19.6 20.3 21.0 20.8 18.8 20.2 21.1 22.9 22.5 21.6 21.5
Millendon (Swan Valley) 17.9 20.3 27.9 24.9 24.1 20.7 21.5 22.8 23.0 24.6 24.2 26.2 22.7 28.6 30.2 17.5 16.7 18.3 21.4 21.3 21.6 22.0 21.7 21.8 21.6 22.2 22.8 23.6 23.6 23.8 26.1
Pearce RAAF 18.3 20.2 28.5 25.4 25.0 22.1 22.5 23.0 22.9 24.9 24.6 26.5 23.2 29.1 31.0 18.1 17.0 17.9 22.2 21.6 21.5 22.2 22.0 21.4 21.8 22.1 22.5 23.6 23.9 24.3 25.8
Perth Airport 18.3 19.9 27.5 23.6 22.1 21.2 21.8 22.8 22.7 24.5 24.0 25.3 22.6 27.9 29.7 17.3 17.1 17.9 21.2 21.1 21.6 22.2 21.9 21.5 21.0 21.8 22.2 23.4 23.6 23.5 26.3
Perth Metro 18.0 19.6 27.1 24.0 22.0 20.4 21.3 22.2 22.4 24.2 24.0 24.9 22.3 28.0 27.6 18.0 16.7 17.4 21.2 20.9 20.8 21.8 21.2 21.1 20.5 21.7 22.1 23.3 23.3 23.6 26.5
Rottnest Island 17.3 18.8 26.1 23.6 22.8 20.5 19.3 20.3 18.8 22.5 23.0 22.7 20.1 21.6 24.8 18.7 15.0 15.5 20.2 21.0 20.0 21.0 20.2 20.9 18.0 19.7 20.8 21.7 22.0 23.6 23.3
Swanbourne 18.3 19.6 28.0 23.6 22.6 20.6 20.3 21.7 21.8 24.4 23.6 22.5 22.5 24.3 26.8 18.9 16.3 16.1 20.3 21.2 20.5 21.8 21.1 20.5 19.4 21.3 21.9 23.3 23.4 24.7 25.0
Values are the maximum temperature, usually in the 24 hours from 9 am on the day indicated,
and typically occurred in the afternoon of that day.
Temperatures coloured according to their difference
from the long-term average for the period
-10.0 -9.0 -8.0 -7.0 -6.0 -5.0 -4.0 -3.0 -2.0 -1.0 0.0 +1.0 +2.0 +3.0 +4.0 +5.0 +6.0 +7.0 +8.0 +9.0 +10.0 °C Grey outline marks highest
and lowest for the period


Daily minimum temperatures for May 2019

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
Bickley 7.7 4.0 5.0 9.5 11.5 12.0 8.6 10.2 6.1 7.1 7.1 10.2 10.2 8.1 11.4 15.0 3.9 3.6 3.5 8.4 10.8 8.0 10.8 9.0 8.8 7.1 7.1 7.5 6.5 8.7 11.5
Garden Island HSF 12.4 10.1 11.5 16.0 16.2 16.4 12.2 15.5 10.5 10.4 9.0 10.2 10.2 11.1 9.4 13.7 8.9 7.8 9.0 11.8 14.2 10.7 13.6 12.0 12.7 11.1 11.9 12.6 12.8 14.4 16.4
Gosnells City 7.0
11.0 13.3 12.9 11.0
10.5
8.5 11.5 8.0 9.0
10.0 15.0 3.5
4.3 8.0 12.6

7.5 9.0 10.6
12.5 11.5

Jandakot Aero 6.0 4.6 3.1 12.4 11.6 15.8 5.9 8.3 6.0 6.4 4.0 5.2 6.7 7.3 6.1 13.2 3.3 0.4 -0.1 7.8 11.9 6.7 8.7 6.0 6.6 4.9 10.2 7.7 10.2 12.7 12.9
Karnet
4.5

10.0 11.9 6.5
6.0 8.0
6.5 6.6 8.6
12.8 2.0 1.1 2.0 7.3 8.5 5.2 8.3 5.9 5.4 6.9
8.9 8.8

Mandurah 11.6 8.5 10.0 15.6 15.4 15.2 12.2 14.9 10.4 10.3 10.7 11.5 11.1 11.4 12.0 14.1 7.2 6.5 8.3 11.8 13.9 10.4 12.8 11.0 11.3 10.3 10.1 11.7 12.4 14.2 16.0
Millendon (Swan Valley) 5.6 6.7 8.7 9.8 8.5 14.6 5.6 7.0 6.2 8.6 5.3 5.8 5.6 6.1 6.6 12.6 1.4 0.5 0.7 6.3 10.5 5.0 7.9 4.4 6.5 6.4 11.4 12.2 11.1 14.3 16.2
Pearce RAAF 4.4 4.8 9.3 11.0 8.8 13.7 4.7 5.7 6.8 5.4 7.9 5.0 4.1 4.1 7.3 13.0 0.6 -0.3 2.7 7.9 10.5 5.8 8.0 4.1 5.6 6.7 11.7 13.1 11.9 12.6 15.7
Perth Airport 5.9 4.8 9.0 10.2 9.7 16.0 5.0 7.5 7.7 7.4 7.6 7.9 5.8 6.5 9.5 13.7 1.7 1.5 3.9 8.3 11.2 6.3 8.9 4.3 5.4 5.3 10.1 11.3 10.1 13.1 13.8
Perth Metro 9.2 5.5 6.6 11.2 11.3 16.2 7.2 9.5 8.1 7.9 6.1 7.7 8.8 8.5 7.8 14.5 5.3 2.1 1.6 9.6 12.7 6.8 10.4 6.7 7.6 5.3 9.9 10.7 9.8 12.8 13.2
Rottnest Island 12.6 11.0 12.5 16.0 17.8 15.7 15.4 15.5 11.4 13.9 15.5 15.1 15.5 14.0 16.2 18.1 11.1 9.8 11.7 13.7 14.0 14.1 16.1 15.2 14.2 12.9 12.9 14.2 13.5 15.0 16.4
Swanbourne 10.2 8.0 9.8 15.4 13.7 16.2 11.1 12.5 8.4 9.8 10.9 10.6 11.4 10.1 12.1 16.6 6.8 4.8 5.4 11.0 13.2 10.2 13.3 10.2 10.7 9.5 10.7 12.0 11.0 13.5 15.6
Values are the minimum temperature, usually in the 24 hours to 9 am on the day indicated,
and typically occurred that morning.
Temperatures coloured according to their difference
from the long-term average for the period
-10.0 -9.0 -8.0 -7.0 -6.0 -5.0 -4.0 -3.0 -2.0 -1.0 0.0 +1.0 +2.0 +3.0 +4.0 +5.0 +6.0 +7.0 +8.0 +9.0 +10.0 °C Grey outline marks highest
and lowest for the period


Daily rainfall for May 2019

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
Anketell - - - 6.5 - 5.0 1.2 - - - - - - - - 0.8 2.4 - - 4.6 0.2 - - - - - - - - - -
Bickley - - - 3.0 0.2 16.0 0.2 0.2 - - - - 0.2 - - 0.2 3.2
- 4.4 0.2 - - - 0.2 - - - - - -
Bungendore - - - 1.8 0.4 12.2 1.0 0.2 - - - - - 0.2 - 0.4 1.8 - 0.2 5.8 0.4 - 0.2 0.2 - 0.2 - - - - -
Chidlow - - - 2.9 ? 4.2 - - - - - - - - - - 4.6 - ? 2.8 - - - - - - - - - - 0.5
Garden Island HSF - - - 3.0 - 2.4 - - - - - - - - - 1.8 1.2 - - 10.6 3.0 - - - - - - - - - -
Gidgegannup - - - 2.0 0.2 7.6 - 0.2 - - - - - - - 0.2 5.6 - - 3.8 - - 0.2 - 0.2 - - - - - -
Gosnells City - - - 3.2 0.2 -
- - - - - - - - - - - - 6.2 - - - - - - - - -

Huntly - - - 5.2 0.8 15.0 0.2 0.2 - - - - 2.0 - - 5.0 12.5 - - 6.6 2.0 4.0 - - 4.0 3.0 - 0.2 - - -
Jandakot Aero - - - 1.6 - 7.8 0.2 - - - - - - - - 0.4 2.8 - - 10.6 1.0 - - - - - - - - - -
Jarrahdale 0.2 - - 6.0 - 12.0 - 0.2 - 0.2 0.2 0.2 0.2 0.4 0.2 0.8 5.8 0.2 0.2 8.0 0.2 0.2 0.2 0.4 0.2 0.2 - - - - -
Karnet

? ? 0.1 14.4 0.6 - - - - - 0.2 - ? 1.2 5.2 - - 4.2 - 0.2 0.1 - - - - - -

Karragullen North - - - 5.0 ? 7.8 - - - - - - - - - 1.0 3.4 - ? 11.2










Maida Vale - - - - 2.0 6.6 - - - - - - - - - 1.2 2.2 - - 3.2 0.4









Mandurah - - - 2.0 - 4.0 - - - - - - - - - 3.8 2.8 - - 9.4 0.6 - - - - - - - - - -
Midland - - - ? ? 29.8 - - - - - - - - - 3.8 - ? ? 5.6










Millendon (Swan Valley) - - - 2.4 0.2 4.2 - - - - - - - - - - 4.0 - - 4.8 0.4 - - - - - - - - - -
Mosman Park - - - - - 27.0
























Mount Solus 0.2 - - 6.0 0.2 13.4 0.4 - - - - - 0.2 - - 0.4 12.4 - - 5.2 - - - 0.2 0.6 - - - - - -
Muchea - - - 0.4 - 4.8 - - - - - - - - - 0.4 3.6 - - 3.0 0.2 0.2 - 0.2 - 0.2 - - - - -
Mundaring - - - ? 5.6 11.4 - - - - - - - - - 1.0 - - - 11.8 0.2









Pearce RAAF - - - 1.2 - 3.0 - 0.2 - - - - - - - - 4.2 - - 9.2 - 0.2 - - - - - - - - -
Perth Airport - - - 1.6 0.2 5.6 - - - - - - - - - 0.2 1.8 - - 2.8 - - - - - - - - - - -
Perth Metro - - - 2.0 0.2 7.2 - - - - - - - - - 0.2 1.8 - - 6.0 0.4 - - - - - - - - - -
Pinjarra South - - - 4.0 - 6.8 - 0.2 - - - - - - - 5.0 5.4 - - 5.0 - - - - - - - - - - -
Roleystone - - - 4.2 ? 6.2 0.4 0.2 - - - - - - - 1.2 3.0 - ? 7.8 - - - - - - - - - - 0.2
Rottnest Island - - - 1.0 - 1.4 - - - - - - - - - 0.4 2.8 - - 3.4 0.8 2.6 - - - - - - - - -
Serpentine - - - 4.4 - 7.2 - - - - - - - - - 1.0 4.8 - - 4.6 0.2 - - - - - - - - - -
Swanbourne - - - 2.8 0.2 4.8 - - - - - - - - - 0.2 1.8 - - 3.8 1.6 - - - - - - - - - -
Tamala Park (Mindarie) - - - 3.0 - 3.1 - - - - - - - - - 5.0 0.6 - - 8.8 2.0 - - - - - - - -

Wanneroo - - - ? ? 6.8 - - - - - - - - - 1.0 2.6 ? ? 7.8 0.2









Werribee - - - 1.0 - 3.6 - - 0.2 - - - - - - - 5.2 0.2 - 1.4 0.2 - - 0.2 - - 0.2 - - - -
Whiteman Park - - - 2.4 - 5.6 - - - - - - - - - 0.6 3.0 - - 6.4 0.4









Most values are the precipitation in the 24 hours to 9 am on the day indicated. Days marked with ? are part of a longer accumulation, which is shown on the final day.
Values over 100 mm have been rounded to the nearest whole millimetre.
Days marked with - have a rainfall report of zero; days left blank have no rainfall report (which often indicates no rain fell).
Rainfalls coloured
according to the amount
0 1.0 5.0 10.0 15.0 25.0 50.0 100 150 200 300 400 600 millimetres

Notes

The Monthly 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.

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 3 pm on Saturday 1 June 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
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