The coolest September in Perth for 26 years

Rainfall near average: The city received 91.0 millimetres of rainfall over 17 days in September compared with the average of 81 mm over 15 days. Last September Perth recorded 35.2 mm over 11 days. Total rainfall for January to September this year was 803.6 mm compared with the average of 771 mm, making it the wettest January to September period since 1992. The wettest January to September total on record was 1244.2 mm in 1945.

Mean daily maximum temperature below average: Perth's mean daily maximum temperature in September was 19.2 degrees Celsius making it the lowest mean maximum temperature for September since the 19.1 degrees in 1979. The average is 20.1 degrees Celsius. Daily maxima ranged from a cool 15.5 degrees on the 9th to a warm 25.2 degrees on the 16th.

Mean daily minimum temperature below average: Perth's mean daily minimum temperature in September was 8.9 degrees Celsius, compared with the average of 9.5 degrees. Minima ranged from a very cold 1.5 degrees on the 1st and the 10th, the lowest daily minimum temperature for Perth in September on record, to a mild 13.9 degrees on the 7th.

Mean daily sunshine hours below average: Perth's mean daily sunshine hours in September was 7.3, compared to the average of 7.7 hours. (This is a preliminary figure based on the available data at the time of the media release. Please check updated mean sunshine hours from Daily Weather Observations for Perth in early October).

September monthly mean temperature and sunshine
Element	2005	Long- term Average	Highest	Year	Lowest	Year	Records Commence
Maximum Temperature (°C)	19.2	20.1	22.6	1987	16.8	1915	1897
Minimum Temperature (°C)	8.9	9.5	12.4	1988	8.0	2004	1897
Sunshine (hours per day)	7.3	7.7	8.8	4 years	4.9	1907	1898
September monthly rainfall and rain days
Element	2005	Long-term Average	Highest	Year	Lowest	Year	Records Commence
Rainfall (mm)	91.0	81	199.1	1923	8.7	1916	1876
Rain days	17	15	26	1915	4	1877	1876

September daily extremes
Element	2005	Date	Extreme	Date	Records Commence
Highest daily maximum (°C)	25.2	16/09/2005	32.7	30/09/1918	1897
Lowest daily maximum (°C)	15.5	09/09/2005	11.4	17/09/1917	1897
Highest daily minimum (°C)	13.9	07/09//2005	19.5	08/09/1916	1897
Lowest daily minimum (°C)	1.5	01 & 10/09/2005	1.7	11/09/2004	1897
Wettest 24 hours to 9am (mm)	20.0	06/09/2005	51.8	14/09/1984	1876

Climate of Perth in October

October days are generally mild, with more frequent sunshine and some warm to hot days. There is typically a marked reduction in rainfall compared with September. The October rainfall average is 53 mm on 9 days.

October monthly mean temperatures and sunshine
Element	Average	Highest	Year	Lowest	Year	Records Commence
Maximum temperature (°C)	22.8	25.8	1969	18.8	1924	1897
Minimum temperature (°C)	11.2	14.2	1969	9.3	1910	1897
Sunshine (hours per day)	9.6	10.9	2000	5.5	1898	1898
October monthly rainfall and rain days
Element	Average	Highest	Year	Lowest	Year	Records Commence
Rainfall (mm)	53	199.9	1890	1.0	1969	1876
Rain days	9	22	1898	1	1969	1876

October daily extremes
Element	Highest	Date	Lowest	Date	Records Commence
Maximum temperature (°C)	37.3	29/10/1967	11.9	08/10/1932	1897
Minimum temperature (°C)	22.2	29/10/1979	2.2	06/10/1994	1897
Rainfall 24 hours to 9am (mm)	68.2	18/10/1995	n/a	n/a	1876

Hot days in October: On average, Perth has about one hot day, when the maximum temperature is 32 degrees or higher. The greatest number of such days in October was four in 1969. The last time Perth recorded an October day over 32 degrees was in 2000, with 34.2 degrees on the 28th

Earliest 35-degree day of the season: The earliest 35-degree maximum temperature of the season was on 20 October 1996 when 36.9 degrees was recorded, the fourth highest maximum temperature for October on record.

Cold nights in October: On average, Perth can expect one cold night when the minimum temperature is 5 degrees or less. There was one such night in October last year.

October top 10 hottest			October top 10 coldest
Position	Date	Max temp °C	Position	Date	Max temp°C
1	29 October 1967	37.3	1	08 October 1932	11.9
2	26 October 1961	37.2	2	17 October 1924	12.7
3	29 October 1979	37.1	3	18 October 1947	13.0
4	20 October 1996	36.9	4	05 October 1968	13.1
5	30 October 1988	36.3	5	09 October 1903	13.7
6	26 October 1972	36.2	6	02 October 1933	14.2
7	24 October 1960	35.9	7	03 October 1962	14.3
8	25 October 1961	35.6	7	05 October 1965	14.3
9	30 October 1922	35.2	9	08 October 1956	14.4
9	24 October 1981	35.2	10	01 October 1947	14.6

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 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 Glenn Cook tel: (08) 9263 2222 on weekdays.

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