Tuesday, 2 October 2007 - Monthly Climate Summary for Perth - Product Code:IDCKGC11L0

Above average rainfall for September in Perth

September Rainfall - above average: The city received 100.6 mm of rainfall over 16 days in September compared with the average of 81 mm on about 15 days. This was the wettest September since the 102.0 mm in 2003. The wettest day in September 2007 was the 12th when 23.6 mm was recorded. Last September Perth registered 86.4 mm on 13 days.

January to September rainfall - below average: The total rainfall for January to September this year was 637.4 mm on 99 days compared with the average of 768 mm on about 92 days. For the same period last year Perth recorded its second driest nine months (January to September) period on record with 426.8 mm on 80 days.

Mean daily maximum temperature - near average: Perth's mean daily maximum temperature in September was 20.2°C compared with the average 20.1°C. Daily maxima ranged from a cool 17.6°C on the 7th and 13th to a warm 27.6°C on the 3rd.

Mean daily minimum temperature - near average: Perth's mean daily minimum temperature in September was 9.6°C, compared with the average of 9.5°C. Daily minima ranged from a cold 4.3°C on the 10th to a mild 14.6°C on the 27th.

September monthly mean temperature and sunshine
Element

2007

Long- term Average

Highest

Year

Lowest

YearRecords Commence
Maximum
Temperature (°C)
20.2
20.1
22.6
1987
16.8
1915
1897
Minimum
Temperature (°C)
9.6
9.5
12.4
1988
8.0
2004
1897
Sunshine
(hours per day)
7.6
7.7
8.8
4 years
4.9
1907
1898
September rainfall and rain days
Element2007Long-term AverageHighestYearLowestYearRecords Commence
Rainfall (mm)
100.6
81
199.1
1923
8.7
1916
1876
Rain days
16
15.1
26
1915
4
1877
1876

September daily extremes
Element2007DateExtremeDate

Records Commence

Highest daily maximum (°C)
27.6
03/09/2007
32.7
30/09/1918
1897
Lowest daily maximum (°C)
17.6
7 & 13/09/2007
11.4
17/09/1917
1897
Highest daily minimum (°C)
14.6
27/09/2007
19.5
08/09/1916
1897
Lowest daily minimum (°C)
4.3
10/09/2007
1.5
* Twice
1897
Wettest 24 hours to 9am (mm)
23.6
12/09/2007
51.8
14/09/1984
1876

* Denotes the lowest minimum temperature for September on record on the following dates: 1 and 10 September 2005.

Climate of Perth in October

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

October monthly mean temperatures and sunshine
ElementAverageHighest YearLowest Year

Records
Commence

Maximum temperature
(°C)
22.8
25.8
1969
18.8
1924
1897
Minimum temperature
(°C)
11.1
14.2
1969
9.3
1910
1897

Sunshine
(hours per day)

9.6
10.9
2000
5.5
1898
1898
October rainfall and rain days
Element
Average
Highest
Year
Lowest
Year
Records Commence
Rainfall (mm)
53
199.9
1890
1.0
1969
1876
Rain days
9.3
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 one hot day when the maximum temperature is 32°C or higher in October. The greatest number of such days was four in 1969. The last time Perth recorded an October day over 32°C was in 2000, with 34.2°C on the 28th.

Earliest 35°C day of the season: The earliest 35°C or greater maximum temperature of the season was on 20 October 1996 when 36.9°C 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°C or less. There were no such nights in October 2006.

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) and Glenn Cook Western Australia Climate Services Centre
on, tel: (08) 9263 2222, office hours.