Rainfall below average: The city received 5.0 mm of rainfall over 5 days in December compared with the average of 13 mm over 4 days. Historically, December rainfall has ranged from 0.0 mm in 5 years to 80.7 mm in 1952. Last December Perth recorded 2.6 mm on 3 days.

Mean daily maximum temperature lowest on record: Perth's mean maximum temperature in December was 23.7 degrees Celsius, the lowest mean maximum temperature on record. The previous record was 24.3 degrees in 1922. Daily maxima ranged from a mild 19.7 degrees on the 5th to a hot 32.5 degrees on the 18th.

Mean daily minimum temperature well below average: Perth's mean daily minimum temperature in December was 14.0 degrees Celsius, compared with the average of 16.4 degrees. Daily minima ranged from a cool 8.9 degrees on the 24th to a mild 17.5 degrees on the 19th and 20th.

Mean daily sunshine hours below average: Perth's mean daily sunshine hours in December was 10.5, compared with the average of 11.8 hours.

Climate of Perth in January

It is midsummer in Perth in January, and days are generally sunny and either warm or hot. The low humidity that generally occurs on days of high temperature makes conditions more tolerable. Sea-breezes that blow across the coastal plain on most afternoons moderate the temperature. Hot spells, usually of two or three days' duration, are commonly followed by cooler conditions for a similar period. On average, January is Perth's driest month with 9 mm of rain over two days.

Very hot days in January: On average, Perth can expect one day when the maximum temperature is 40 degrees or higher. The greatest number of such days in January was four in 1961, 1965 and 1968. The last time Perth recorded such a day in January was on 11 January 2004 when 40.5 degrees was recorded.

Hot days in January: On average, Perth can expect twelve days when the maximum temperature is 32 degrees or higher. The highest number of such days in January was 24 in 1962, when the record highest mean maximum temperature for January (34.4 degrees) was set.

Perth at a Glance 2005

Total rainfall for 2005 was 874.8 mm, compared with the long-term average of 859 mm, making it the wettest year since the 888.6 mm in 1996. The wettest year on record was 1945 with 1338.8 mm. Perth's wettest month in 2005 was June with 251.0 mm, 72.0 mm above the average of 179 mm. The wettest day in 2005 was 7 June with 52.2 mm. Only four months exceeded their monthly mean in 2005, March, May, June and September. In July Perth recorded only 62.8 mm, making it the second driest July on record, the driest being July 1876 with 61.5 mm.

Perth's mean daily maximum temperature was 23.5 degrees Celsius, which was the lowest since the 23.2 degrees in 1986 and compares with an average of 24.5 degrees. The mean daily minimum temperature was 12.3 degrees, which was the lowest since the 11.9 degrees in 2001 and compares with an average of 12.8 degrees. The highest maximum temperature in 2005 was 42.0 degrees on 15 February and the highest minimum temperature occurred on 17 March when 23.4 degrees was recorded. The lowest maximum temperature was a chilly 11.5 degrees on 12 June while the lowest minimum temperature of 0.2 degrees occurred on 7 and 12 July.

During 2005 Perth recorded two days when the maximum temperature was 40.0 degrees or higher, the least number of such days since the two days in 2002; the long-term average is three.

Perth recorded 25 nights when the minimum temperature was 5 degrees or less, the least number of such nights since the 17 nights in 2000; the average is 26.

Perth's average daily sunshine in 2005 was 8.4 hours which was below the long-term average of 8.8 hours.

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 Mt Lawley site, the most significant changes of this kind relate to temperature (minima much moreso than maxima) and rain days. For that reason, current mean temperature and rain-day data quoted here are based only on readings from the 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.

Further information:
John Relf (JR) or John Cramb, both (08) 9263 2222.