Warm, sunny December with above average rainfall in ACT

  • Well above average maximum temperatures, 8th highest on record
  • Above average minimum temperatures, 11th highest on record
  • 8th consecutive December with above average minimum temperatures
  • Above average rainfall
  • Sunny month, well above average sunshine hours

Rainfall

Canberra Airport recorded a total rainfall of 77.0 mm during December, which is above the historical average1 of 53.8 mm, or 143% of the normal total. It is the third consecutive December with above average rainfall. The rain occurred on 9 rain days (historic average is 8 rain days). Nearly three-quarters of the rainfall occurred during the last week, when an inflow of moist tropical air associated with ex-tropical cyclone Laurence produced widespread rain over the ACT.

Slightly higher rainfall totals were recorded in southwest suburbs while lower totals were recorded in the east. The highest total for December was 111.4 mm at Mount Ginini AWS and 101.6 mm at Tuggeranong Creek, while the lowest was 66.8 mm at Kingston. Moderate to heavy rain associated with an inflow of tropical moisture on the 28th produced the highest daily total for December of 45.4 mm at Tuggeranong Creek and 27.4 mm at Canberra Airport. This was also the wettest day of the year at Canberra Airport.

Temperatures

Generally warm to hot and sunny days prevailed in Canberra during December, with only the last week being cool and cloudy. The mean maximum temperature at Canberra Airport was 28.8 °C, which is +2.7 °C above the historical average of 26.1 °C, and the 8th highest on record. There were 13 hot days (maximum over 30 °C), the highest since December 1994 (when 15 days). Normally Canberra would expect 7 hot days during December. The highest temperature in the ACT during December was 38.8 °C at Canberra Airport on the 17th. Prevailing warm W-NW winds (for 52% of the time) and sunny days contributed towards the high daytime temperatures.

Night-time temperatures were also above average, with a mean minimum temperature of 12.5 °C at Canberra Airport, which is +1.2 °C above the historic average. This is now the 8th consecutive December with above average minimum temperatures in the ACT. At Canberra Airport, daily minimum temperatures ranged from a low of 6.2 °C on the 1st to a high of 17.9 °C on the 25th. The lowest temperature in the ACT during December was -1.7 °C at Mount Ginini AWS (elev 1760 metres) on the 1st.

Wind

Prevailing winds were between N and W for 75% of the time during December, which is close to normal. There were 5 strong wind days during the month, above the normal 3 windy days for December. The strongest winds in the ACT were on the 17th associated with a sharp low pressure trough with gusts reaching 78 km/h at Canberra Airport and Mount Ginini.

Other phenomena

Canberra experienced a sunny month with an average of 10.5 hours of sunshine per day, compared to the historic December average of 9.4 hours per day. Although thunderstorms were reported over the southern parts of the ACT on the 27th, no storm activity was recorded at Canberra Airport during December. There were several days of dust and smoke haze reducing visibility to 10 km, however, no fogs or frosts were recorded at Canberra Airport.

Further information

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Extremes in December 2009
Hottest day 38.8 °C at Canberra Airport on the 17th
Warmest days on average 29.0 °C at Tuggeranong AWS
Coolest days on average 28.8 °C at Canberra Airport
19.3 °C at Mount Ginini AWS
Coldest day 18.2 °C at Canberra Airport on the 26th
10.0 °C at Mount Ginini AWS on the 1st
Coldest night 6.2 °C at Canberra Airport on the 1st
-1.7 °C at Mount Ginini AWS on the 1st
Coolest nights on average12.4 °C at Tuggeranong AWS
7.8 °C at Mount Ginini AWS
Warmest nights on average 12.5 °C at Canberra Airport
Warmest night 17.9 °C at Canberra Airport on the 25th
Wettest overall 101.6 mm at Tuggeranong Creek
111.4 mm at Mount Ginini AWS
Driest overall66.8 mm at Kingston
Wettest day45.4 mm at Tuggeranong Creek on the 28th
Highest wind gust 78 km/h at Canberra Airport and Mount Ginini AWS on the 17th




Summary statistics for December 2009
Maximum temperatures
for December
(°C)
Minimum temperatures
for December
(°C)
Rainfall
for December
(millimetres)
Mean for
December
2009
Diff
from
average
Highest for
December
2009
Mean for
December
2009
Diff
from
average
Lowest for
December
2009
Total for
December
2009
Average
for
December
Rank of
December
2009
Fraction of
December
average
Canberra Airport 28.8 +2.7 38.8 17th 12.5 +1.2 6.2 1st 77.0 53.8 high 143%
Mount Ginini AWS 19.3   27.3 17th 7.8   -1.7 1st 111.4
Tuggeranong AWS 29.0 +1.9 38.2 17th 12.4 +0.4 7.0 2nd 98.4 54.5 high 181%

Notes

The Monthly Climate Summary is prepared to list the main features of the weather in Canberra area using the most timely and accurate information available on the date of publication; it will generally not be updated. Later information, including data that has had greater opportunity for quality control, will be presented in the Monthly Weather Review, usually published in the fourth week of the month.

This statement has been prepared based on information available at 3 pm on Monday 4 January 2010. Some checks have been made on the data, but it is possible that results will change as new information becomes available.

Averages are long-term means based on observations from all available years of record, which vary widely from site to site. They are not shown for sites with less than 20 years of record, as they cannot then be calculated reliably.
The median is sometimes more representative than the mean of long-term average rain.

The Rank indicates how rainfall this time compares with the climate record for the site, based on the decile ranking (very low rainfall is in decile 1, low in decile 2 or 3, average in decile 4 to 7, high in decile 8 or 9 and very high is in decile 10).
The Fraction of average shows how much rain has fallen this time as a percentage of the long-term mean.

Further information

Media
(03) 9669 4057
Enquiries