Monday 1 December, 2008 - Monthly Climate Summary for Perth - Product Code: IDCKGC11LO

Cool and wet November in Perth

November Rainfall - very much above average The city received 57.8 mm of rainfall over 13 days in November which is the wettest November since 1991, then 71.4 mm, and ranked the seventh wettest November on record since records commenced in 1876. The average for November is 22 mm on about 6 days. Last November Perth registered 5.2 mm on 3 days (fifth driest on record).

Perth's top 10 wettest Novembers
Year
Total Rainfall (mm)
Rain Days
Ranking
1984
73.2
10
1
1991
71.4
11
2
1916
70.6
8
3
1924
66.3
13
4
1946
65.7
9
5
1956
58.6
9
6
2008
57.8
13
7
1992
57.0 *
11
8
1880
53.8
7
9
1965
51.2
14
10
* The figure is estimated, observations not available.

Year to date rainfall - near average: The total rainfall for January to November this year was 796.2 mm on 110 days. The January to November average is 842 mm on about 107 days. Last year Perth recorded 685.0 mm on 110 days for the same period.

Mean daily maximum temperature - very much below average: Perth's mean daily maximum temperature in November was 23.6°C, which was the lowest mean daily maximum temperature for November since the 23.2°C in 1991. The average for November is 26.3°C.  This November was in fact cooler than October 2008, when the mean daily maximum temperature was 24.0°C, and this has only occurred on four previous occasions for Perth. Daily maxima ranged from a mild 18.9°C on the 6th to a warm 29.5°C on the 19th. Last November, Perth recorded it's warmest November on record with a mean daily maximum temperature of 28.5°C.

Nil days of 30°C or higher in November:  November 2008 was the first November since 1964 to see Perth without a daily maximum temperature of 30°C or higher. Since 1897, only five Novembers had previously had no days of 30ºC or above. Last November, Perth recorded 12 days with a daily maximum temperature of 30°C or higher, the equal highest number for November along with 2001. In October 2008, Perth recorded 6 such days, a record highest number for October. 

Mean daily minimum temperature - below average: Perth's mean daily minimum temperature in November was 12.4°C, the lowest November mean minimum recorded at the Mt Lawley site since it was established in 1993, and below the average of 14.2°C. Daily minima ranged from a cool 6.5°C on the 7th, to a mild 16.1°C on the 11th.

November monthly mean temperature and sunshine
Element

2008

Long- term Average

Highest

Year

Lowest

Year Records Commence
Maximum
Temperature (°C)
23.6
26.3
28.5
2007
21.5
1971
1897
Minimum
Temperature (°C)
12.4
14.2
16.9
1982
11.9
1954
1897
Sunshine
(hours per day)
10.2
10.7
12.3
2007
5.1
1965
1898
November rainfall and rain days
Element 2008 Long-term Average Highest Year Lowest Year Records Commence
Rainfall (mm)
57.8
22
73.2
1984
0.0
1891
1876
Rain days
13
5.9
14
3 years
0
1891
1876

November daily extremes
Element 2008 Date Extreme Date

Records Commence

Highest daily maximum (°C)
29.5
19/11/2008
40.3
*Several
1897
Lowest daily maximum (°C)
18.9
06/11/2008
15.8
02/11/1919
1897
Highest daily minimum (°C)
16.1
11/11/2008
25.1
24/11/1920
1897
Lowest daily minimum (°C)
6.5
07/11/2008
5.0
18/11/2004
1897
Wettest 24 hours to 9am (mm)
17.4
23/11/2008
39.1
29/11/1956
1876

* Denotes the highest daily maximum temperature recorded on 24 November 1913 and 11 November 2003.

Climate of Perth in December

December is typically a dry month and days are generally sunny and warm to hot. On most afternoons a sea breeze moderates the temperature. December is Perth's sunniest month on average with 11.6 hours of sunshine per day.

December mean temperatures and sunshine
Element Average Highest Year Lowest Year

Records
Commence

Maximum temperature
(°C)
28.7
31.7
1931
23.7
2005
1897
Minimum temperature
(°C)
16.2
19.6
1977
13.9
2005
1897

Sunshine
(hours per day)

11.6
12.6
2000
8.0
1925
1898
December rainfall and rain days
Element
Average
Highest
Year
Lowest
Year
Records Commence
Rainfall (mm)
13
80.7
1951
0.0
5 years
1876
Rain days
3.9
14
1913/44
0
5 years
1876

December daily extremes
Element
Highest
Date
Lowest
Date
Records Commence
Maximum temperature (°C)
44.2
26/12/2007
14.9
17/12/1952
1897
Minimum temperature (°C)
27.1
18/12/1979
7.9
07/12/2007
1897
Rainfall 24 hours to 9am (mm)
46.7
03/12/1951
n/a
n/a
1876

Very hot days: Perth can expect about one day in December when the maximum temperature is 40°C or higher. The highest total number of 40°C or higher days in December days is two, and this has occurred on six occasions since 1897. The last time Perth recorded a very hot day in December was on 26 December 2007 when 44.2°C was recorded, the highest temperature recorded for Perth in December.

Hot days: On average, Perth can expect about eight days in December when the maximum temperature is 32°C or higher. The highest total number of hot days in December was eighteen in 1931, Perth's warmest December on record with a mean maximum temperature of 31.7°C. Last December, Perth recorded 7 hot days.

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, 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 Yanhui Blockley - (08) 9263 2222 during business hours.