Rains tumble during a hot January in the ACT

Rainfall: A total of 79 millimetres of rain fell at Canberra airport in January, well above the average of 59.9 mm. Rain fell over eight days, which was average. There were eight thunderstorm days compared with the average of four. There was no hail reported at the airport, which was average. The most notable thunderstorm activity was as follows:
6 January: Small hail and heavy rain at Queanbeyan.
16 January: Very heavy rain across the region, some due to embedded thunderstorms.
17 January: 1 centimetre diameter hail in some southern suburbs during the early evening.
28 January: 2 cm hail at Tidbinbilla and some heavy rain.
Rainfall across the ACT was quite variable for the month, with the heaviest falls on 17 January. The lowest reading of 54.4 mm was at Lanyon, while the highest of 115.6 mm was at Mawson.

Temperature: The mean daily maximum temperature of 30.4 degrees Celsius was 2.6 degrees above the long-term average of 27.8 degrees, and the highest since January 2003 when it was 30.5 degrees. The record highest is 31.6 degrees in January 1981. Maximum temperatures reached 30.0 degrees or more on 18 days compared with the average of 10. They reached 35.0 degrees or above on six days compared with the average of two. The highest maximum of 39.9 degrees on 1 January was in the highest 5 per cent of maximum temperatures ever recorded at the airport. The record is 41.4 degrees on 31 January 1968. By contrast, the lowest maximum temperature of 18.2 degrees on 18 January was the coolest day since 7 January 1997 (18.1 degrees).
The mean daily minimum temperature of 16.5 degrees was 3.5 degrees above the long-term average of 13.0. This is the second warmest minimum on record. The record is 16.6 degrees in 1981. As both maximum and minimum temperatures were well above average, the mean daily temperature (average of daily maximum and minimum temperatures) of 23.5 degrees was also well above the average of 20.4, and the second highest on record. The highest is 24.1 degrees in January 1981.

Other: The average 24-hour wind run at 2 metres was 197 kilometres a day, very close to the average of 200 km/day. There were no strong winds, compared with the January average of one day. The monthly evaporation of 260.8 mm was just above the average of 252.2 mm, while the mean daily sunshine of 8.4 hours a day was less than the average of 9.4 hr/day. There were no fogs for the month (average zero) and no frosts (average zero). The average daily pressure of 1012.7 hectopascals was close to the January mean of 1012.2 hPa.

Of note: The above-average relative humidity was of interest in January. This was due to the combination of the first decent monsoon in the Australian tropics for at least three years, and slow moving high-pressure systems in the Tasman Sea. Both helped direct highly moisture-laden air over the region.

Summary for Canberra airport, January 2006

Mean maximum temperature: 30.4°C (av 27.8°C)
Highest maximum temperature: 39.9°C (1 January)
Lowest maximum temperature: 18.2°C (18 January)
Mean minimum temperature: 16.5°C (av 13.0°C)
Highest minimum temperature: 21.5°C (28 January)
Lowest minimum temperature: 11.9°C (8 January)
Mean daily temperature: 23.5°C (av 20.4°C)
Lowest grass temperature: 7.8°C (3 January)
Total monthly rainfall: 79.0 mm (av 59.9 mm)
Total monthly evaporation: 260.8 mm (av 252.2 mm)
Mean daily sunshine: 8.4 hr/day (av 9.4 hr/day)
Mean daily pressure: 1012.7 hPa (av 1012.2 hPa)
Mean daily wind run (at 2 metres): 197 km/day (av 200 km/day)

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

Ends