Wednesday, 1 July 2009 - Monthly Climate Summary for Perth - Product Code: IDCKGC11LO

Near Average Rainfall for June in Perth

Rainfall - near average: The city received 156.2 mm of rainfall over 19 days in June compared with the average of 177 mm over about 15 days.  The wettest day in June 2009 was the 29th when 23.2 mm was recorded.  Historically, June rainfall has ranged from 24.6 mm in 2006, to 476.1 mm in 1945. Last year in June, Perth recorded 142.0 mm on 14 days.

Year to date rainfall - well below average: The total rainfall for January to June this year was 222.4 mm on 35 days, which was the driest January to June period since the 134.6 mm in 2006. The average for this period is normally 381 mm on about 43 days. The total for the same period last year was 417.0 mm on 45 days.

Mean daily maximum temperature - near average: Perth's mean daily maximum temperature in June was 18.8°C, compared with the average of 19.3°C, which was the lowest mean daily maximum temperature for June since the 18.0°C in 2005. Daily maxima ranged from a cold 12.8°C on the 23rd, the coldest day for four years, to a warm 26.2°C on the 1st, the warmest June day for 25 years since the 26.8°C on 4 June 1984.

January to June mean daily maximum temperature - second highest on record: Perth's mean daily maximum temperature for the January to June period was 27.4°C, compared with the average of 26.4°C. This was the second highest mean daily maximum temperature for this period since records commenced in 1897, the highest being 27.6°C in 1978.

Perth's top 10 mean maximum temperatures
for year to date (January-June)
Year
Mean Maximum Temperatures (°C)
Departure from normal
Ranking
1978
27.6
+1.2
1
2009
27.4
+1.0
2
1972
27.1
+0.7
3
1976
27.0
+0.6
4
1988
27.0
+0.6
4
1985
26.9
+0.5
6
1996
26.9
+0.5
6
2008
26.9
+0.5
6
1962
26.8
+0.4
9
1998
26.7
+0.3
10
1999
26.7
+0.3
10
2003
26.7
+0.3
10
2004
26.7
+0.3
10

Mean daily minimum temperature - near average: Perth's mean daily minimum temperature in June was 8.9°C, compared with the average of 8.6°C. Daily minima ranged from a cold 3.4°C on the 14th to a mild 13.2°C on the 1st.

Cold nights: Perth recorded four cold nights this June with a minimum temperature of 5 degrees or less, compared with the average of six nights. Last June Perth recorded 11 cold nights.
 

June monthly mean temperature and sunshine
Element

2009

Long- term Average

Highest

Year

Lowest

Year Records Commence
Maximum
Temperature (°C)
18.8
19.3
20.6
1983
15.9
1898
1897
Minimum Temperature (°C)
8.9
8.6
12.8
1964
5.8
2006
1897
Sunshine
(hours per day) #
6.2
5.9
7.4
2006
2.9
1945
1898
June rainfall and rain days
Element 2009 Long-term Average Highest Year Lowest Year Records Commence
Rainfall (mm)
156.2
177
476.1
1945
24.6
2006
1876
Rain days
19
15.4
27
1918/1970
5
2006
1876

(# This is a preliminary figure based on the available data at the time of the media release. Please check updated mean sunshine hours from Daily Weather Observations for Perth in early July).

June daily extremes
Element 2009 Date Extreme Date

Records Commence

Highest daily maximum (°C)
26.2
01/06/2009
28.1
05/06/1975
1897
Lowest daily maximum (°C)
12.8
 23/06/2008
8.8
26/06/1956
1897
Highest daily minimum (°C)
13.2
01/06/2009
18.7
12/06/1988
1897
Lowest daily minimum (°C)
3.4
14/06/2009
−0.7
17/06/2006
1897
Wettest 24 hours to 9am (mm)
23.2
29/06/2009
99.1
10/06/1920
1876

Climate of Perth in July
July is one of Perth's coldest and wettest months. Many days are cloudy, wet and windy, though there are generally some sunny days with light winds and cold nights.

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

Records
Commence

Maximum temperature (°C)
18.3
19.9
1976/1977
15.7
1910
1897
Minimum temperature (°C)
8.0
11.4
1921
5.3
1997
1897

Sunshine (hours per day)

6.0
7.5
1918
3.2
1926
1898
July monthly rainfall and rain days
Element
Average
Highest
Year
Lowest
Year
Records Commence
Rainfall (mm)
170
425.1
1958
61.5
1876
1876
Rain days
17.5
29
1946
6
1918
1876

July daily extremes
Element
Highest
Date
Lowest
Date
Records Commence
Maximum temperature (°C)
26.3
Twice
10.5
09/07/1906
1897
Minimum temperature (°C)
16.1
12/07/1898
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.

Warm days in July: On average, Perth can expect six days when the maximum temperature is 20°C or more. The greatest number of such days in July was 14 days in 1976 and 1977. Last July, Perth recorded four such days.

Cold days in July: On average, Perth can expect two days when the maximum temperature is 15°C or less. The greatest number of such days in July was 12 in 1916. Last July, Perth recorded two such days.

Cold nights in July: Perth has a mean of eight cold nights when the minimum temperature is 5°C or lower. The greatest number of such nights was 16 in 1998 and 2001. Last July, Perth recorded eight such nights.

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:
John Relf (JR) and Pat Ward Western Australia Climate Services Centre
on, tel: (08) 9263 2222, office hours.