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. 

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.

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

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

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.

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

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

Latest 32°C 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 32°C or greater occurred on 3 May 1907, with 32.2°C. 

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.