Tuesday,2 June 2009 - Monthly Climate Summary for Perth - Product Code: IDCKGC11LO
Perth experiences its warmest May on record
Mean daily maximum temperature - highest on record: Perth's mean daily maximum temperature in May was 24.4°C, compared with the average of 22.3°C. This was the highest mean daily maximum temperature for May for Perth since records commenced 1897. The previous highest was 24.0°C in May 2003. Daily maxima in May 2009 ranged from a cool 16.1°C on the 23rd to a warm 28.5°C on the 5th.
January to May mean daily maximum temperature - second highest on record: Perth's mean daily maximum temperature for the January to May period was 29.1°C, compared with the average of 27.8°C. This was the second highest mean daily maximum temperature for this period since records commenced in 1897; the highest being 29.4°C in 1978.
Mean daily minimum temperature - below average: Perth's mean daily minimum temperature in May was 9.5°C, compared with the average of 10.8°C. Daily minima ranged from a cold 3.3°C on the 25th to a mild 16.2°C on the 21st.
Rainfall - very much below average: The city received 46.0 mm of rainfall on 4 days in May compared with the average of 118 mm on about 12 days. The wettest day was the 23rd when 21.0 mm was recorded. This was Perth's driest May since the 31.0 mm on 9 days in 2006. Historically, May rainfall has ranged from 14.1 mm in 1964, to 308.1 mm in 1879. Last May Perth registered 59.6 mm on 13 days.
Rain days - record low: Perth recorded its least number of rain days for May on record with only 4 days compared with the average of about 12 days. The previous record was 5 rain days in May 1913.
Dry start to May:
Year to date rainfall - second driest on record: The total rainfall for January to May this year was 66.2 mm recorded on 16 rain days, making it the second driest start to a year since the 64.3 mm in 1972. The average for January to May is 204 mm whilst last year Perth recorded 275.0 mm in the same period.
Mean daily sunshine hours - highest on record: Perth's mean daily sunshine hours in May was 8.1 hours per day, compared with the average of 6.7 hours per day. This was the highest mean daily sunshine hours for Perth for May since sunshine records commenced in 1898. The previous record was 7.9 hours in 2000.
Perth in June
Warm days in June: On average, Perth can expect 12 days when the maximum temperature is 20°C or more. The greatest number of such days in June was 21 days in 1983. Last June, Perth recorded 17 such days.
Cold days in June: On average, Perth can expect one day when the maximum temperature is 15°C or less. The greatest number of such days in June was 10 in 1931 and 1955. Last June, Perth recorded one such day.
Cold nights in June: Perth has a mean of six cold nights in June when the minimum temperature is 5°C or lower. The greatest number of such nights was 13 in 2006. Last June, Perth recorded 11 such nights.
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 (Mt 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 (Mt 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.