Friday, 2 December 2005

SEASONAL CLIMATE SUMMARY - ACT

Wettest ACT spring in five years

This year the territory had its wettest spring season since 2000, however the period was characterised not only by higher than average rainfall, but higher than average temperatures as well.

Rainfall: Canberra Airport recorded 245 millimetres of rain, which fell over 40 of the 91 days of spring, exceeding the long-term average of 180.7 mm over 30 days. September was especially wet, with 100.6 mm of rain falling over 14 days. October’s rainfall came close to the long-term average while the November rainfall was slightly above.

Thunderstorms were reported on a total of 11 days compared to the seasonal average of seven. Severe thunderstorms on 13 and 24 October produced hail up to about 2 centimetres in diameter. A severe thunderstorm on 26 November produced heavy rain and large hail in some northern Canberra suburbs. Hail was sighted on a total of five days during the season.

Temperature: Overall the average daily temperature for the season was 13.8 degrees, just above the long-term average of 12.7 degrees. The mean daily maximum temperature of 19.8 degrees was half a degree higher than the long-term seasonal average, with every month of the season recording above average temperatures. Despite this, no especially warm days of more than 30.0 degrees occurred during spring - on average there are usually two days with temperatures reaching more than 30.0 degrees in November.

The mean daily minimum temperature of 7.8 degrees exceeded the long-term average of six degrees with September, October and November all recording above average temperatures. Frost was reported on just 12 mornings (ten in September, two in October). This is well below the average of 21. Fog was seen on two days, which is below the seasonal average of six.

Other: The mean daily sunshine for the season was eight hours per day, compared to the springtime average of 8.3 hours per day. The mean daily wind run was 199 kilometres, much less than the long-term average of 216 km. Strong winds were reported on nine days with the strongest wind gust recorded reaching 72 kilometres per hour from the north on 29 September. The mean atmospheric pressure, which is an average of the 9am and 3pm values, was 1015.2 hectopascals, matching the springtime average. Evaporation totalled 409.8 millimetres which is well below the seasonal average of 464.0 mm. This was due to increased cloud cover, increased humidity and lighter than average winds for the season.

Summary for Canberra airport, Spring 2005

Mean maximum temperature: 19.8°C (av 19.3 °C)
Highest maximum temperature: 28.5°C (22 November)
Lowest maximum temperature: 10.6°C (12 September)
Mean minimum temperature: 7.8°C (av 6.0 °C)
Highest minimum temperature: 15.6°C (1 November)
Lowest minimum temperature: minus 1.4°C (3 September)
Mean daily temperature: 13.8°C (av 12.7°C)
Lowest grass temperature: minus 4.1°C (3 September)
Total spring rainfall: 245.0 mm (av 180.7 mm)
Total spring evaporation: 409.8 mm (av 464.0 mm)
Mean daily sunshine: 8.0 hr/day (av 8.3 hr/day)
Mean daily pressure: 1015.2 hPa (av 1015.2 hPa)
Mean daily wind run (at 2 metres): 199.0 km/day (av 216.0 km/day)

Further information:
Ewan Mitchell, Canberra Meteorological Office, tel: (02) 6249 6269, e-mail: ewanm@bom.gov.au

Ends