Tuesday, 4 March 2008 - Monthly Climate Summary for Perth - Product Code:IDCKGC11L0

Wettest April on record for Perth

Rainfall - record high: The city received 153.6 mm of rainfall in April on 13 rain days compared with the average of 44 mm on 7 days. This was Perth's wettest April since records commenced in 1876. The previous highest rainfall for April on record was 148.8 mm in 1926. The wettest day in April 2008 was on the 6th when 58.6 mm was recorded, which was the fourth wettest April day in Perth on record and the wettest day in Perth in 6 years, since the 69.6 mm on 17 April 2002.  Last April, Perth registered a total rainfall of 76.4 mm on 6 days. 

Perth's top 10 wettest Aprils
Year
Rainfall (mm)
Rain days
Ranking
2008
153.6
13
1
1926
148.8
19
2
1882
126.2
15
3
1955
125.2
13
4
1951
120.7
15
5
1937
103.0
10
6
1889
101.4
8
7
1947
100.7
11
8
1931
100.5
10
9
1980
98.1
16
10

Year to date rainfall - well above average: The total rainfall for January to April this year was 215.4 mm recorded on 18 rain days, making it the second wettest such period on record and the wettest since the 296.9 mm in 1955. The average is 85 mm on 16 days. Last year Perth recorded 105.2 mm on 20 days for the first four months of the year.

Perth's top 10 wettest first 4 months
(January to April)
Year
Rainfall (mm)
Rain days
Ranking
1955
296.9
25
1
2008
215.4
18
2
1926
213.7
33
3
1990
202.2
31
4
1992
198.0
22
5
2000
193.8
17
6
1934
188.6
21
7
1915
175.4
27
8
1968
159.8
36
9
1961
158.5
32
10

Mean daily maximum temperature - below average: Perth's mean daily maximum temperature in April was 24.2C, compared with the average of 25.6C. Daily maxima ranged from a cool 18.8C on the 19th and 21st to a hot 33.1C on the 14th.

Mean daily minimum temperature - below average: Perth's mean daily minimum temperature in April was 12.5C, compared with the average of 13.6C. Daily minima ranged from a cool 7.0C on the 21st to a mild 18.5C on the 8th.

April monthly mean temperature and sunshine
Element

2008

Long- term Average

Highest

Year

Lowest

Year Records Commence
Maximum
Temperature (C)
24.2
25.6
28.2
1978/1999
21.0
1968
1897
Minimum Temperature (C)
12.5
13.6
17.3
1978
11.6
1914
1897
Sunshine
(hours per day)
8.3
8.2
9.3
1920
4.4
1926
1898
April rainfall and rain days
Element 2008 Long-term Average Highest Year Lowest Year Records Commence
Rainfall (mm)
153.6
44
148.8
1926
0.0
3 years
1876
Rain days
13
6.5
19
1926
0
3 Years
1876

April daily extremes
Element 2008 Date Extreme Date

Records Commence

Highest daily maximum (C)
33.1
14/04/2008
37.6
09/04/1910
1897
Lowest daily maximum (C)
18.8
* Twice
13.6
16/04/1919
1897
Highest daily minimum (C)
18.5
08/04/2008
24.4
02/04/1913
1897
Lowest daily minimum (C)
7.0
21/04/2008
4.1
20/04/1914
1897
Wettest 24 hours to 9am (mm)
58.6
06/04/2008
69.6
17/04/2002
1876

*Lowest maximum temperature recorded on 19th and 21st.

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
Element Average Highest Year Lowest 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
12.2
25
1921
5
1913
1876

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

Latest 30C day of the season: On average, Perth experiences a maximum temperature of 30C or higher in May in six years out of ten. The latest 30C day in the autumn season occurred on 9 May 1962, with 30.0C.

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

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 Yanhui Blockley Western Australia Climate Services Centre
on, tel: (08) 9263 2222, office hours.