Monday, 1 August 2005

MONTHLY CLIMATE SUMMARY - ACT

Above-average July rainfall and temperatures in the ACT

July 2005 was a month of above-average rainfall and temperatures. The 24-hour rainfall total of 48.0 millimetres on 9 July was the highest ever 24-hour total at Canberra Airport in July. One of the highest ever pressures for the airport was also recorded.

Temperature: The mean daily maximum temperature of 12.7 degrees Celsius was 1.5 degrees above the long-term average of 11.2. The mean daily minimum temperature of 1.4 degrees was 1.5 degrees above the long-term average of minus 0.1 degrees. There were 17 frost days in the ACT in July, four less than the average of 21. The mean daily temperature (the average of maximum and minimum temperatures) of 7.0 degrees was well above the long-term average of 5.6 degrees.

Rainfall: July rainfall of 86.4 mm at the airport was well above the average of 41.0 mm and broke the significant dry spell experienced since January. Rain was recorded over 17 days, well above the average of nine rain days. Rainfall of 48.0 mm over 24 hours on 9 July was a new July record for the airport. The previous best was 43.8 mm on 11 July 1991. Some good rain was recorded across the ACT this month, including 81.2 mm at Ainslie and 117 mm at Tidbinbilla. There were five days of fog for the month compared with an average of seven. There were no thunderstorms, which was average, no hail and no snow.

Other: It was a windier month than normal, with an average daily wind run at 2 metres of 196 kilometres a day. The long-term average for July is 182 km/day. There was one day of strong winds compared with an average of two days. The average daily pressure was 1023.0 hectopascals, well above the long-term average of 1020.5 hPa. The 9am pressure recorded at the airport on 20 July was 1041.9 hPa, one of the highest on record for any month. The mean daily sunshine of 6.3 hours a day was above the average of 5.7 hr/day, while the monthly evaporation of 49.2 mm was less than the long-term average of 51.8 mm.

Summary for Canberra airport, July 2005

Mean maximum temperature: 12.7°C (av 11.2°C)
Highest maximum temperature: 17.5°C (31 July)
Lowest maximum temperature: 9.3°C (8-9 July)
Mean minimum temperature: 1.4°C (av minus 0.1°C)
Highest minimum temperature: 8.7 °C (26 July)
Lowest minimum temperature: minus 4.2°C (23 July)
Lowest grass temperature: minus 6.8°C (23 July)
Total monthly rainfall: 86.4 mm (av 41.0 mm)
Total monthly evaporation: 49.2 mm (av 51.8 mm)
Mean daily sunshine: 6.3 hr/day (av 5.7 hr/day)
Mean daily pressure: 1023.0 hPa (av 1020.5 hPa)
Mean daily wind run (at 2 metres): 196 km/day (av 182 km/day)

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

Ends