Tuesday, 1 May 2007 - Monthly Climate Summary for Perth - Product Code: IDCKGC11L0

Wettest April for five years in Perth

Rainfall - above average: The city received 76.4 mm of rainfall over 6 days in April compared with the average of 43 mm over about 7 days. This was the wettest April since the 96.0 mm in 2002. The wettest day in April 2007 was the 16th when 40.2 mm was recorded, which was the tenth wettest April day on record, and the wettest April day since the 69.6 mm on 17 April 2002. Historically, April rainfall has ranged from 0.0 mm on 3 occasions, to 148.8 mm in 1926. Last April Perth registered 25.4 mm rainfall.

Year to date rainfall - above average: The total rainfall for January to April this year was 105.2 mm recorded on 20 days making it the wettest such period since the 122.8 mm in 2003. The average is 85 mm.

Mean daily maximum temperature - near average: Perth's mean daily maximum temperature in April was 25.2°C, compared with the average of 25.7°C. Daily maxima ranged from a mild 20.4°C on the 25th to a hot 36.0°C on the 4th, which was the highest daily maximum temperature in Perth for April since the 36.2°C on 4 April 2001.

Mean daily minimum temperature - below average: Perth's mean daily minimum temperature in April was 12.4°C, compared with the average of 13.7°C. Daily minima ranged from a cool 5.8°C on the 28th to a mild 17.6°C on the 15th.

April monthly mean temperature and sunshine
Element

2007

Long- term Average

Highest

Year

Lowest

YearRecords Commence
Maximum
Temperature (°C)
25.2
25.7
28.2
1978/1999
21.0
1968
1897
Minimum Temperature (°C)
12.4
13.7
17.3
1978
11.6
1914
1897
Sunshine
(hours per day)
8.5
8.1
9.3
1920
4.4
1926
1898
April rainfall and rain days
Element2007Long-term AverageHighestYearLowestYearRecords Commence
Rainfall (mm)
76.4
43
148.8
1926
0.0
3 years
1876
Rain days
6
6.6
19
1926
0
3 Years
1876

April daily extremes
Element2007DateExtremeDate

Records Commence

Highest daily maximum (°C)
36.0
04/04/2007
37.6
09/04/1910
1897
Lowest daily maximum (°C)
20.4
25/04/2007
13.6
16/04/1919
1897
Highest daily minimum (°C)
17.6
15/04/2007
24.4
02/04/1913
1897
Lowest daily minimum (°C)
5.8
28/04/2007
4.1
20/04/1914
1897
Wettest 24 hours to 9am (mm)
40.4
16/04/2007
69.6
17/04/2002
1876

Climate of Perth in May
Rainfall shows a dramatic increase in May as cold fronts become more frequent. The average rainfall in May is almost three times that of April. However, pleasantly mild days with cool nights also occur and on average there are almost seven hours of sunshine per day.

May monthly mean temperatures and sunshine
ElementAverageHighest YearLowest Year

Records
Commence

Maximum temperature (°C)
22.3
24.0
2003
18.7
1931/1956
1897
Minimum temperature (°C)
10.9
13.8
1972/2005
8.8
2000
1897

Sunshine (hours per day)

6.7
7.9
2000
3.4
1905
1898
May monthly rainfall and rain days
Element
Average
Highest
Year
Lowest
Year
Records Commence
Rainfall (mm)
119
308.1
1879
14.1
1964
1876
Rain days
12.1
25
1921
5
1913
1876

May daily extremes
Element
Highest
Date
Lowest
Date
Records Commence
Maximum temperature (°C)
34.3
01/05/2002
11.5
23/05/1995
1897
Minimum temperature (°C)
20.8
01/05/1983
1.3
11/05/1914
1897
Rainfall 24 hours to 9am (mm)
76.2
17/05/1942
n/a
n/a
1876

Cold days in May: On average Perth has one cold day when the maximum temperature is 15 degrees or lower. The greatest number of such days was three in 1936. The most recent cold day Perth recorded in May was 11.5 degrees on 23 May 1995, the coldest May day on record.

Latest 30-degree day of the season: On average Perth experiences one day in May when the maximum temperature is 30 degrees or higher. The latest 30-degree day in the autumn season occurred on 9 May 1962, with exactly 30 degrees recorded.

Latest 32-degree day of the season: Hot days are very rare in May with only one in every five years on average. The latest maximum temperature of 32 degrees or greater occurred on 3 May 1907, with 32.2 degrees registered.

Note: Official Perth observations have been recorded at several different sites with varying instrumentation over the years, and these changes can affect the continuity of the climate record. For the current Perth (Mount Lawley) site, the most significant changes of this kind relate to temperature and rain days. For that reason, current mean temperature and rain-day data quoted here are based only on readings from the Perth (Mount Lawley) site, which commenced observations in 1993. Sunshine recordings are from Perth Airport and for similar reasons current means use only Perth Airport data, which commenced in 1993.

Further information:
John Relf (JR) and Glenn Cook Western Australia Climate Services Centre
on, tel: (08) 9263 2222, office hours.