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Monday, 2 September 2002
MONTHLY CLIMATE SUMMARY - WESTERN AUSTRALIAN REGIONAL OFFICE
Rainfall: August rainfall in Perth this year was well below average.
The city received 81.2 millimetres over 14 days compared with the average of
135mm over 17 days. It was Perth's driest August since 1987, when only
67.4mm was recorded. The heaviest daily rainfall last month was 15.8mm on
9 August, the lowest August extreme daily rainfall for 11 years, after
13.8mm fell on 1 August, 1991. Historically, August rainfall has ranged
from a low of 11.8mm in 1902 to 318.3mm in 1945. Total rainfall for the
eight-month period ending 31 August was 580.4mm, below the average of 699mm.
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| August averages | |||||||
|---|---|---|---|---|---|---|---|
| Element | Aug. 2002 |
Average | Highest average |
Year | Lowest average |
Year | Years of record |
| Maximum temp (°C) | 18.6 | 18 | 20.3 | 1902 | 16.3 | 1932 | 106 |
| Minimum temp (°C) | 7.1 | 8 | 11.5 | 1977,83 | 6.9 | 1956 | 106 |
| Sunshine (hours/day) | 7.5 | 7.2 | 8.4 | 1902 | 4.2 | 1945 | 105 |
| August rainfall averages and extremes | |||||||
| Element | Aug. 2002 |
Average | Highest | Year | Lowest | Year | Years of record |
| Rainfall (mm) | 81.2 | 135 | 318.3 | 1945 | 11.8 | 1902 | 127 |
| Rain days | 14 | 17 | 29 | 1955 | 4 | 1902,78 | 127 |
| August daily extremes | |||||
|---|---|---|---|---|---|
| Element | Aug. 2002 |
Date | Extreme | Date | Years of record |
| Highest daily maximum (°C) | 25.3 | 24th | 27.8 | 14/8/1940 | 106 |
| Lowest daily maximum (°C) | 15.3 | 15th | 9.9 | 5/8/1951 | 106 |
| Lowest daily minimum (°C) | 1.4 | 13th | 1.3 | 21/8/2000 | 106 |
| Highest daily minimum (°C) | 12.7 | 25th | 16.6 | 13/8/1976 | 106 |
| Wettest 24-hour period (mm) | 15.8 | 9th | 73.9 | 14/8/1945 | 123 |
Climate of Perth in September
September is the first month of spring. The warming and drying tend to accelerate in Perth. Monthly rainfall and the number of wet days typically fall, while maximum and minimum temperatures and the number of sunshine hours increase.
| September monthly averages | ||||||
|---|---|---|---|---|---|---|
| Element | Average | Highest average |
Year | Lowest average |
Year | Years of record |
| Maximum temp (°C) | 20 | 22.6 | 1987 | 16.8 | 1915 | 105 |
| Minimum temp (°C) | 9 | 12.4 | 1988 | 8.7 | 1919,52 | 105 |
| Sunshine (hours/day) | 7.6 | 8.8 | *many | 4.9 | 1907 | 104 |
| September rainfall and rain days | ||||||
| Element | Average | Highest | Year | Lowest | Year | Years of record |
| Rainfall (mm) | 80 | 199.1 | 1923 | 8.7 | 1916 | 126 |
| Rain days | 14 | 26 | 1915 | 4 | 1877 | 126 |
* The highest mean sunshine hours of 8.8 was recorded in 1914, 1929, 1954 and 1987.
| September daily extremes | ||||||
|---|---|---|---|---|---|---|
| Element | Highest | Date | Lowest | Date | Years of record |
|
| Maximum temperature (°C) | 32.7 | 30/09/1918 | 11.4 | 17/9/1917 | 105 | |
| Minimum temperature (°C) | 19.5 | 8/9/1916 | 1.8 | 23/9/1998 | 105 | |
| Rainfall (mm) 24 hrs to 9am | 51.8 | 14/9/1984 | - | - | 122 | |
Warm days in September: On average, Perth has about two days when the maximum temperature is 25 degrees or higher. The record is 10 days in Perth's warmest September on record, 1987, when the mean maximum temperature was 22.6 degrees.
Cold days in September: On average, Perth has about one day when the maximum temperature is 15 degrees or lower. The record is four days in 1903. There were no such days in 2001.
Cold nights in September: On average, Perth has about two nights when the minimum is 5 degrees or lower. The record is six in 1998. There were two nights when the minimum was 5 degrees or lower in 2001.
Earliest 32-degree day of the season (hot day): The earliest 32-degree maximum temperature of the season was on 18 September 1988, when 32.3 degrees was recorded, the second highest maximum temperature for September on record.
| September top 10 hottest | September top 10 coolest | ||||
|---|---|---|---|---|---|
| Position | Date | Max temp°C |
Position | Date | Max temp°C |
| 1 | 30 September 1918 | 32.7 | 1 | 17 September 1917 | 11.4 |
| 2 | 18 September 1988 | 32.3 | 2 | 4 September 1931 | 11.6 |
| 3 | 22 September 1961 | 32.2 | 3 | 1 September 1931 | 12.1 |
| 4 | 26 September 1961 | 31.3 | 4 | 16 September 1937 | 12.5 |
| 5 | 14 September 1987 | 30.9 | 5 | 14 September 1947 | 12.7 |
| 6 | 28 September 1990 | 30.7 | 6 | 17 September 1915 | 12.9 |
| 6 | 20 September 1994 | 30.7 | 6 | 19 September 1923 | 12.9 |
| 8 | 12 September 1939 | 30.6 | 6 | 12 September 1950 | 12.9 |
| 8 | 21 September 1954 | 30.6 | 9 | 20 September 1904 | 13.0 |
| 8 | 27 September 1954 | 30.6 | 10 | 12 September 1916 | 13.1 |
| - | - | - | 10 | 10 September 1925 | 13.1 |
Note: Official Perth observations have been recorded at several
different sites over the years. Changes in site location can affect both
temperature and rainfall readings. Due to a relatively short period of
record for the current site, temperature averages have been estimated to
represent that site.
Ends
Further information:
John Relf (JR), or Glenn Cook, tel:(08) 9263 2222 or, after hours, the senior forecaster.