March rains in ACT less than average but more than median

March rainfall in the ACT this year was less than the average of 51.7 millimetres but more than the median of 31.6 mm. Daytime temperatures were near average, while nights were slightly cooler than average.

Rainfall: A total of 40.2 mm of rain fell at the airport over five days in March, well below the average of 51.7 mm over seven days. There was one thunderstorm day on the afternoon of 21 March. The monthly average is two thunderstorm days. More rain fell around the central areas than to the north or south. The highest recording was 54.8 mm at the Botanic Gardens. The lowest of 23.8 mm was at Wanniassa.

Although the March total of 40.2 mm was less than the arithmetic average, it was more than the median figure of 31.6 mm. The arithmetic average takes in the extreme events, while the median is the 50 per cent level – that is, half of all the months of March have had rainfall of more than 31.6 mm. The large difference in the arithmetic average and the median total indicates that March rainfall in the ACT is quite variable. To have a lower-than-average rainfall total is not that unusual.

Temperature: The mean daily minimum temperature of 10.1 degrees Celsius was less than the average 10.6 degrees. The mean daily maximum temperature of 24.3 degrees was very close to the average of 24.4. The mean daily temperature for the month was 17.2 degrees, slightly less than the average of 17.5. There were seven days in March when the temperature reached 30.0 degrees or more compared with the average of three days. The run of four consecutive days of 30 degrees or more – from 12 to 15 March – was the longest warm spell for the month since 1998. The first frost of the season was on 6 March. On average there are zero frosts in March. There were no fogs compared with the monthly average of two.

Other: The mean daily sunshine of 8.6 hours a day was much more than the average of 8.0 hr/day. It was slightly windier than normal, with a mean daily wind run of 185 kilometres a day compared with the average of 167 km/day. There was only one day of strong winds compared with the average of two days. Monthly evaporation of 183 mm was more than the average of 171.1 mm. The mean daily pressure of 1018.1 hectopascals was greater than the average of 1016.5 hPa.

Summary for Canberra airport, March 2005

Mean maximum temperature: 24.3 degrees (av 24.4 degrees)
Highest maximum temperature: 34.1 degrees (15 March)
Lowest maximum temperature: 17.5 degrees (17 March)
Mean minimum temperature: 10.1 degrees (av 10.6 degrees)
Highest minimum temperature: 17.4 degrees (2 March)
Lowest minimum temperature: 2.7 degrees (6 March)
Mean daily temperature: 17.2 degrees (av 17.5 degrees)
Lowest grass temperature: minus 1.7 degrees (6 March)
Total monthly rainfall: 40.2 mm (av 51.7 mm)
Total monthly evaporation: 183.0 mm (av 171.1 mm)
Mean daily sunshine: 8.6 hr/day (av 8.0 hr/day)
Mean daily pressure: 1018.1 hPa (av 1016.5 hPa)
Mean daily wind run (at 2 metres): 185 km/day (av 167 km/day)

Further information:
Clem Davis, Canberra Meteorological Office, tel: (02) 6249 6269, e-mail: c.davis@bom.gov.au

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