Friday 1 August 2008 - Monthly Climate Summary for Perth - Product Code:IDCKGC11L0

An average July for Perth

Rainfall - near average: The city received 179.4 mm of rainfall on 20 days in July 2008 compared to the average of 170 mm on about 17 days. The wettest day in July 2008 was the 30th when 30.6 mm was recorded. Historically, total July rainfall has ranged from 61.5 mm in 1876, to 425.1 mm in 1958. In July 2007, Perth recorded 179.4 mm on 19 days, remarkably similar to July 2008.

Year to date rainfall - near average: The total rainfall for January to July this year was 596.2 mm recorded on 65 days compared with the average of 551 mm on about 61 days. This is the wettest start to the year (January to July) since 610.0 mm was recorded in the same period in 1995. The total for the same period last year was 406.0 mm on 63 days.

Mean daily maximum temperature - near average: Perth's mean daily maximum temperature in July was 17.9°C, compared with the average of 18.4°C. Daily maxima ranged from a cold 14.1°C on the 31st, to a warm 20.8°C on the 27th.

Mean daily minimum temperature - near average: Perth's mean daily minimum temperature in July was 7.3°C,  compared with the average of 8.0°C. Daily minima ranged from a cold 0.7°C on the 6th and 7th to a mild 13.4°C on the 11th.

July monthly mean temperature and sunshine
Element

2008

Long- term Average

Highest

Year

Lowest

Year Records Commence
Maximum
Temperature (°C)
17.9
18.4
19.9
1976/1977
15.7
1910
1897
Minimum Temperature (°C)
7.3
8.0
11.4
1921
5.3
1997
1897
Sunshine
(hours per day)
5.1
6.1
7.5
1918
3.2
1926
1898
July rainfall and rain days
Element 2008 Long-term Average Highest Year Lowest Year Records Commence
Rainfall (mm)
179.4
170
425.1
1958
61.5
1876
1876
Rain days
20
17.3
29
1946
6
1918
1876

 

July daily extremes
Element 2008 Date Extreme Date

Records Commence

Highest daily maximum (°C)
20.8
27/07/2008
26.3
†Twice
1897
Lowest daily maximum (°C)
14.1
31/07/2008
10.5
09/07/1906
1897
Highest daily minimum (°C)
13.4
11/07/2008
16.1
12/07/1898
1897
Lowest daily minimum (°C)
0.7
*Twice
0.0
Twice
1897
Wettest 24 hours to 9am (mm)
30.6
30/07/2008
95.0
29/07/1987
1876

*Denotes the lowest minimum temperature for July 2008 occurred on both the 6th and 7th.

†Denotes the lowest minimum temperature for July on record on the following dates: 15 July 1997 and 27 July 1998.

Denotes the highest maximum temperature for July on record on the following dates: 17 & 18 July 1976.

Climate of Perth in August
August heralds the end of winter and generally shows signs of the forthcoming change in the season. Mean temperatures are generally similar to those in July, but there is a slight reduction in the mean rainfall. Mean sunshine hours increase, with an extra 1.0 hours per day on average.

August monthly mean temperatures and sunshine
Element Average Highest Year Lowest Year

Records
Commence

Maximum temperature (°C)
18.7
20.3
1902
16.3
1932
1897
Minimum temperature (°C)
8.3
11.5
1977/1983
6.9
1956/2001
1897

Sunshine (hours per day)

7.1
8.4
1902
4.2
1946
1898
August monthly rainfall and rain days
Element
Average
Highest
Year
Lowest
Year
Records Commence
Rainfall (mm)
135
318.3
1945
11.8
1902
1876
Rain days
16.4
29
1955
4
1902/1978
1876

August daily extremes
Element
Highest
Date
Lowest
Date
Records Commence
Maximum temperature (°C)
27.8
21/08/1940
10.5
09/07/1906
1897
Minimum temperature (°C)
17.0
07/08/2006
0.0
†† Twice
1897
Rainfall 24 hours to 9am (mm)
95.0
29/07/1987
n/a
n/a
1876

†Denotes the highest maximum temperature for July on record on the following dates: 17 & 18 July 1976.

††Denotes the lowest minimum temperature for July on record on the following dates: 15 July 1997 and 27 July 1998.


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