Perth Monthly Climate Summary: September 2006
Close to average September for Perth

Wednesday 4 October, 2006

September Rainfall - near average: The city received 86.4 mm of rainfall over 17 days in September compared with the average of 81 mm over 15 days. The wettest day in September 2006 was the 11th when 22.0 mm was recorded. Last September Perth registered 91.0 mm on 17 days.

Nine-monthly rainfall - very much below average: The total rainfall for January to September this year was 426.8 mm on 80 days making it the second driest such period on record for Perth. The driest was 421.4 mm on 83 days in 1914. The average is 771 mm.

Perth's top 10 driest years to date
(January to September total)
Season
Rainfall (mm)
Rain Days
Ranking
1914
421.4
83
1
2006
426.8
80
2
1940
432.2
76
3
1877
497.9
87
4
1979
501.2
89
5
1977
503.2
75
6
1959
514.0
93
7
1894
522.0
84
8
1969
530.2
79
9
1911
553.6
87
10

Mean daily maximum temperature - near average: Perth's mean daily maximum temperature in September was 20.6°C compared with the average 20.0°C. Daily maxima ranged from a cool 16.4°C on the 1st to a warm 30.5°C on the 29th, the warmest daily maximum temperature for September for twelve years.

Mean daily minimum temperature - near average: Perth's mean daily minimum temperature in September was 10.0°C, compared with the average of 9.4°C. Daily minima ranged from a cold 3.7°C on the 2nd to a mild 15.4°C on the 10th.

September monthly mean temperature and sunshine
Element

2006

Long- term Average

Highest

Year

Lowest

Year Records Commence
Maximum
Temperature (°C)
20.6
20.0
22.6
1987
16.8
1915
1897
Minimum
Temperature (°C)
10.0
9.4
12.4
1988
8.0
2004
1897
Sunshine
(hours per day)
7.9
7.7
8.8
Many
4.2
1907
1898
September rainfall and rain days
Element 2006 Long-term Average Highest Year Lowest Year Records Commence
Rainfall (mm)
86.4
81
199.1
1923
8.7
1916
1876
Rain days
17
15
26
1915
4
1877
1876
September daily extremes
Element 2006 Date Extreme Date

Records Commence

Highest daily maximum (°C)
30.5
29/09/2006
32.7
30/09/1918
1897
Lowest daily maximum (°C)
16.4
01/09/2006
11.4
17/09/1917
1897
Highest daily minimum (°C)
15.4
10/09/2006
19.5
08/09/1916
1897
Lowest daily minimum (°C)
3.7
02/09/2006
1.5
* Twice
1897
Wettest 24 hours to 9am (mm)
22.0
11/09/2006
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 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)
22.7
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
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 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 were two such nights in October 2005.

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

October top 10 warmest
October top 10 coldest
Position
Date
Mix
temp°C
Position
Date
Min
temp°C
1
29 October 1979
22.2
1
06 October 1994
2.2
2
13 October 1991
21.3
2
10 October 2005
2.5
3
20 October 1967
21.0
3
11 October 1996
4.0
4
03 October 1963
20.4
3
11 October 2005
4.0
4
22 October 1977
20.4
5
06 October 1968
4.2
6
31 October 1922
19.9
5
07 October 1994
4.2
6
21 October 1994
19.9
7
10 October 2001
4.3
8
25 October 1983
19.7
7
18 October 2003
4.3
9
15 October 1970
19.5
9
16 October 1931
4.4
10
29 October 1900
19.4
10
02 October 2004
4.5
10
31 October 1936
19.4
-
-
-
10
10 October 1991
19.4
-
-
-

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