Wednesday, 01 October 2008 - Monthly Climate Summary for Perth - Product Code: IDCKGC11LO

A Close to Average September for Perth

Rainfall - near average: The city received 75.8 mm of rainfall over 17 days in September, compared with the average of 81 mm on about 15 days. Nearly half of this rain fell on the 25th, with 21.0 mm recorded in the early hours of the morning and a further 14.2 mm recorded during the day at the Perth Metro site.

Year to date rainfall - near average: The total rainfall for January to September this year was exactly 700.0 mm recorded on 89 days, compared with the average of 767 mm on about 92 days.

Mean daily maximum temperature - near average: Perth's mean daily maximum temperature in September was 20.6°C, compared with the average of 20.1°C. Daily maxima ranged from a mild 16.5°C on the 25th, to a warm 26.5°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. On the 22nd, the Perth Metro site recorded a minimum of 1.0°C, breaking the September record of 1.5°C for lowest daily minimum set on the 1st and 10th of September 2005. Daily minima ranged from 1.0°C to a mild 15.2°C on the 12th and 25th.

Mean sunshine hours - near average: Perth's mean sunshine hours in September was 7.3, compared to the average of 7.7.

September monthly mean temperature and sunshine
Element

2008

Long- term Average

Highest

Year

Lowest

Year Records Commence
Maximum
Temperature (°C)
20.6
20.1
22.6
1987
16.8
1915
1898
Minimum Temperature (°C)
9.6
9.5
12.4
1988
8.0
2004
1898
Sunshine
(hours per day)
7.3
7.7
8.8
4 years
4.9
1907
1898
September rainfall and rain days
Element 2008 Long-term Average Highest Year Lowest Year Records Commence
Rainfall (mm)
75.8
81
199.1
1923
8.7
1916
1876
Rain days
17
15.1
26
1915
4
1877
1876

September daily extremes
Element 2008 Date Extreme Date

Records Commence

Highest daily maximum (°C)
26.5
03/09/2008
32.7
30/9/1918
1897
Lowest daily maximum (°C)
16.5
25/09/2008
11.4
17/09/1917
1897
Highest daily minimum (°C)
15.2
12/09/2008 & 25/09/2008
19.5
08/09/1916
1897
Lowest daily minimum (°C)
1.0
22/09/2008
1.5
01/09/2005 & 10/09/2005
1897
Wettest 24 hours to 9am (mm)
21.0
25/09/2008
51.8
14/09/1984
1876

 

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
9.2
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 34.1°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 night every five years where the minimum temperature is 5°C or less. There was one such night in October 2007 .

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:
Patrick Ward or Yanhui Blockley, Western Australia Climate Services Centre
on, tel: (08) 9263 2222, office hours.