Monday, 3 August 2009 - Monthly Climate Summary for Perth - Product Code: IDCKGC11LO
Near average July for Perth
Rainfall - near average: The city received 149.6
mm of rainfall on 16 days in July 2009, compared to the average of 170
mm on about 17 days. The wettest day in July 2009 was the 19th
when 30.6 mm was recorded. Historically, July rainfall total has
ranged from 61.5 mm in 1876, to 425.1 mm in 1958. Last July Perth recorded
179.4 mm on 20 days.
Year to date rainfall - below average: The total rainfall for January to July this year was 372.0 mm recorded on 51 days, which was the driest January to July period since the 215.6 mm in 2006. The average for this period is 551 mm on about 61 days. The total for the same period last year was 596.4 mm on 65 days.
Mean daily maximum temperature - near average:
Perth's mean daily maximum temperature in July was 17.8°C, compared with
the average of 18.3°C, which was the lowest mean daily maximum temperature
for July for 6 years, since the 17.8°C in 2003. Daily maxima ranged from
a cold 14.3°C on the 20th, to a warm 21.7°C on the 30th, which was the
highest daily maximum temperature for July since the 23.7°C on 18th July
Cold nights: Perth recorded 11 cold nights this July with minimum temperatures of 5°C or less. It was the greatest number of such nights since the eleven in July 2004. On average, Perth can expect eight cold nights in July. In 1998 and 2001, Perth recorded the most number of cold nights for July with 16.
†Denotes the lowest minimum temperature for July on record on the following dates: 15 July 1997 and 27 July 1998.
††Denotes the highest maximum temperature for July on record on the following dates: 17 & 18 July 1976.
Perth in August
Warm days in August: On average, Perth can expect a warm day, when the maximum temperature is 25 degrees or higher, one year in five in August. The greatest number of warm days in August was four in 1914, whilst there were none recorded last year.
Cold days in August: On average, Perth can expect one cold day, when the maximum temperature is 15 degrees or less. The greatest number of such days was 10 in 1917. There were none last August.
Cold nights in August: On average, Perth can expect seven cold nights with a minimum temperature of 5 degrees or less. The greatest number of such nights in August was 15 last year.
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.