Friday, 5 May 2006

MONTHLY CLIMATE SUMMARY

April cool and dry in the ACT

April in Canberra was much drier, cooler, windier and sunnier than average this year.

Temperature: Canberra’s mean daily temperature of 12.2 degrees Celsius in April was well below the average of 13.2 degrees* and was the lowest since 1999. The mean daily maximum temperature of 19.7 degrees was 0.2 degrees below the long-term mean of 19.9. The mean minimum temperature of 4.8 degrees was 1.8 degrees below the long-term average of 6.6. The minimum temperature of minus 3.4 degrees on the morning of 22 April was as cold as has been experienced for this time of year. The coldest on record was minus 3.7 degrees on 25 April 1999. There were 11 frosts recorded in April due to the cold conditions, compared with the average of four.

Rain: There was only 14.8 millimetres of rain recorded over four days at Canberra airport in April, significantly less than the average of 47.1 mm over seven days**. There were no thunderstorms recorded for the month at the airport compared with the average of one day. Rainfall across the ACT was also very much below average. The highest recording was 53.4 mm at Corin Dam and the lowest was 9.8 mm at Gungahlin.

Other: The average wind run in April was 238 kilometres a day, much more than the mean of 148 km/day. There were five days of strong winds compared with the average of one day. The strongest wind gust for the month was 72 km/h recorded on 5 April. No fogs were recorded at the airport compared with the average of three days. The average daily sunshine of 9.0 hours a day was well above the long-term mean of 7.2 hr/day and was the second highest on record for April. The highest was 9.1 hr/day in 1997. Total monthly evaporation was 146.8 mm compared with the average of 108.4 mm. Average daily pressure was 1015.0 hectopascals, much lower than the average of 1019.6 hPa.

* All temperature averages are averages from Canberra airport from 1961 to 1990, which is a convention of the World Meteorological Organization.
** All averages are based on the long-term averages from Canberra airport, from 1939 to 2006, with the exception of those stated in *.

Summary for Canberra airport, April 2006

Mean maximum temperature: 19.7ēC (av 19.9ēC)
Highest maximum temperature: 25.9ēC (12 April)
Lowest maximum temperature: 13.3ēC (6 April)
Mean minimum temperature: 4.8ēC (av 6.6ēC)
Highest minimum temperature: 13.3ēC (20 April)
Lowest minimum temperature: minus 3.4ēC (22 April)
Mean daily temperature: 12.2ēC (av 13.2ēC)
Lowest grass temperature: minus 7.0ēC (22 April)
Total monthly rainfall: 14.8 mm (av 47.1 mm)
Total monthly evaporation: 146.8 mm (av 108.4 mm)
Mean daily sunshine: 9.0 hr/day (av 7.2 hr/day)
Mean daily pressure: 1015.0 hPa (av 1019.6 hPa)
Mean daily wind run (at 2 metres): 238 km/day (av 148.0 km/day)

Further information:
Kenn Batt, Canberra Meteorological Office, tel: (02) 6249 6269, e-mail: k.batt@bom.gov.au

Ends