Autumn rainfall the lowest on record in ACT

The ACT has this year recorded its lowest autumn rainfall total on record. The season was also characterised by very much above average daytime temperatures, while overnight temperatures were close to average.

Rainfall: Only 13.4 millimetres of rain was recorded at Canberra airport over six days in autumn, compared with the long-term average of 146.5 mm over 22 days. This is the lowest autumn rainfall total ever recorded in the ACT. The record for the lowest number of rain days was also broken. In the previous driest autumn in 1965, 23.8 mm of rain was recorded. The previous lowest number of rain days was nine in 1967. Thunderstorm activity was recorded on only one day (in April) this autumn. The average is four days.

Temperature: The average daily maximum temperature for autumn in the ACT was 21.9 degrees Celsius, well above the long-term average of 19.9 degrees. The average daily minimum temperature of 6.9 degrees was just below the long-term average of 7.0 degrees. Maximum temperatures were above average in each month of autumn, while minimum temperatures were close to average in March, well above average in April and well below average in May. The overall average daily temperature for the three months of autumn was 14.4 degrees, above the long-term average of 13.5.

Other: Average daily sunshine for the season was 8.1 hours a day, well above the average of 6.9 hr/day. All months recorded above-average sunshine. May recorded 8.1 hr/day, which was well above average.
The first frost of the year occurred on 8 April, which is the median date for the first frost. There were 22 frosts in autumn, four above average. May had 19 frosts (average 13), though many were very light, and April had three frosts (average five).
The wind run in autumn this year was above average. The average daily wind run was 168.2 kilometres a day compared with the average of 155.2 km/day. There were five days of strong winds (average four days) that were fairly well distributed throughout the season.
There were only four fogs for the season, well below the average of 14 fogs. There were two fogs in March (average two), none in April (average four) and two in May (average eight).
Evaporation for the season was 404.0 mm, well above the average of 346.8 mm.
The average daily pressure of 1019.4 hectopascals was normal. Pressures were below average in March, above average in April and close to average in May.

Summary for Canberra airport, Autumn 2004

Mean maximum temperature: 21.9°C (av 19.9°C)
Highest maximum temperature: 33.2°C (5 March)
Lowest maximum temperature: 11.4°C (24 April)
Mean minimum temperature: 6.9°C (av 7.0°C)
Highest minimum temperature: 17.1°C (8 March)
Lowest minimum temperature: minus 4.0°C (28 May)
Mean daily temperature: 14.4°C (av 13.5°C)
Lowest grass temperature: minus 7.5°C (14 May)
Total autumn rainfall: 13.4mm (av 146.5mm)
Total autumn evaporation: 404.0mm (av 346.8mm)
Mean daily sunshine: 8.1 hr/day (av 6.9 hr/day)
Mean daily pressure: 1019.4 hPa (1019.4 hPa)
Mean daily wind run (at two metres): 168.2 km/day (av 155.2 km/day)

Ends

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