Wednesday 31 July 2002

MONTHLY CLIMATE SUMMARY - WESTERN AUSTRALIAN REGIONAL OFFICE

July rainfall well down on average in Perth

Maximum temperatures: The mean daily maximum temperature for Perth in July of 18.7 degrees Celsius was near the average of 18 degrees. Daily maxima ranged from a cold 14.5 degrees on the 12th to a warm 24.5 degrees on the 17th. Perth experienced two cold day this month, when maximum temperatures were below 15 degrees. The long-term average is four days.
Minimum temperatures: The mean daily minimum temperature for Perth in July of 9.3 degrees was above the average of 8 degrees. Daily minima ranged from a cold 0.9 degrees on the 28th to a mild 13.8 degrees on the 4th. Perth recorded four cold nights in July when the temperature was 5 degrees or less, fewer than the long-term average of seven nights.

July weather averages
Element	July 2002	Average	Highest average	Year	Lowest average	Year	Years of record
Maximum temp (°C)	18.7	18	19.9	1976,77	15.7	1810	106
Minimum temp(°C)	9.3	8	11.4	1921	5.3	1997	106
Sunshine (hours/day)	5.7	6.0	7.5	1918	3.2	1926	105
July rainfall averages and extremes
Element	July 2002	Average	Highest	Year	Lowest	Year	Years of record
Rainfall (mm)	119.8	173	425.1	1958	61.5	1876	127
Rain days	20	18	29	1946	6	1918	127

July daily extremes
Element	July 2002	Date	Extreme	Date	Years of record
Highest daily maximum (°C)	24.5	17th	26.3	17,18/7/1976	106
Lowest daily maximum (°C)	14.5	12th	10.5	9/7/1906	106
Lowest daily minimum (°C)	0.9	28th	0.0	* Twice	106
Highest daily minimum (°C)	13.8	4th	16.1	12/7/1898	106
Wettest 24-hour period (mm)	18.2	19th	95.0	29/7/1987	123

* The lowest minimum temperature on record for any month occurred on 15 July 1997 and 27 July 1998.

Climate of Perth in August

August monthly averages
Element	Average	Highest average	Year	Lowest average	Year	Years of record
Maximum temp (°C)	18	20.3	1902	16.3	1932	105
Minimum temp (°C)	8	11.5	1977,83	6.9	1956	105
Sunshine (hours/day)	7.2	8.4	1902	4.2	1945	104
August rainfall and rain days
Element	Average	Highest	Year	Lowest	Year	Years of record
Rainfall (mm)	135	318.3	1945	11.8	1902	126
Rain days	17	29	1955	4	1902,78	126

August daily extremes
Element	Highest	Date	Lowest	Date	Years of record
Maximum temperature (°C)	27.8	21/8/1940	9.9	5/8/1951	105
Minimum temperature (°C)	16.6	13/8/1976	1.3	21/8/2000	105
Rainfall (mm) 24 hrs to 9am	73.9	14/8/1945	-	-	122

Warm days in August: On average, Perth can expect about five days when the maximum temperature is 20 degrees or higher. The greatest number of warm days in August was 18 in 1902, which was Perth's warmest and driest August on record. There were five such days in August last year.
Cold days in August: On average, Perth can expect about three days when the maximum temperature is 15 degrees or less. The greatest number of such days was 10 in 1917. There was one such day in August last year.

August top 10 hottest			August top 10 coolest
Position	Date	Max temp°C	Position	Date	Max temp°C
1	21 August 1940	27.8	1	5 August 1951	9.9
2	12 August 1914	27.2	2	6 August 1900	10.4
2	11 August 1948	27.2	3	27 August 1968	10.8
2	26 August 1949	27.2	4	11 August 1931	10.9
2	26 August 1998	27.2	5	7 August 1920	11.2
6	20 August 1940	27.1	6	9 August 1917	11.3
7	24 August 1914	27.0	7	7 August 1932	11.5
8	30 August 1902	26.9	8	1 August 1909	11.7
8	12 August 1976	26.9	8	2 August 1932	11.7
10	22 August 1978	26.8	8	25 August 1932	11.7
			8	1 August 1945	11.7

Note: Official Perth observations have been recorded at several different sites over the years. Changes in site location can affect both temperature and rainfall readings. Due to a relatively short period of record for the current site, temperature averages have been estimated to represent that site.

Further information:
John Relf (JR), or Glenn Cook, tel:(08) 9263 2222 or, after hours, the senior forecaster.