Thursday, 3 January 2008 - Monthly Climate Summary for Canberra - Product code IDCKGC1xx0

Canberra in December 2007
Very warm nights, wettest December in 8 years

Summary

  • Highest December rainfall total since 1999
  • 15 rain days - highest December rain day total since 1971
  • Equal third warmest December on record for average minimum temperatures
  • Cloudiest December since 1992

Rainfall

Canberra Airport recorded a total rainfall of 100.6 mm during December, which is significantly above the historical average1 of 52.4 mm. This makes it the wettest December since 1999, and the wettest month since September 2005. There were 15 rain days during December, compared to the average of 8 days, which is the highest December rain day total since 1971.

Much of the rain that fell over Canberra in December was a result of slow moving troughs and upper atmospheric cold pools during the month. Additionally, an unseasonably strong cold front brought heavy rainfall on the 22nd and 23rd of the month.

See a map of total rainfall. See a map of rainfall deciles.

Temperature

The wet and cloudy conditions across Canberra during December produced cooler than average days and warmer than average nights. The mean minimum temperature for Canberra was 13.3ºC, which is 2.0ºC above the historical average1 of 11.3ºC. This makes December 2007the equal 3rd warmest December on record (current record is 13.9ºC set in 1988) for average minimum temperatures, and the warmest December since 1997. It also marks the seventh consecutive December with above average minimum temperatures.

The average maximum temperature for December was 25.1ºC, which is slightly below the historical average of 25.9ºC, and the coolest December since 1999 for average maximum temperatures.

The average mean temperature (the average of the maximum and minimum temperature) was 19.2ºC, which is slightly higher than the historical average of 18.6ºC. This makes it the coolest December since 2001 for average mean temperatures, but marks the eighth consecutive December with above average mean temperatures.

Extremes at Canberra Airport ranged from a high of 35.0ºC on the 30th to a low of 7.5ºC on the 18th. Corresponding extremes for Tuggeranong ranged from a high of 35.0ºC on the 30th to a low of 6.8ºC on the 18th.

See a map of mean maximum temperatures. See a map of maximum temperature anomalies.

See a map of mean minimum temperatures. See a map of minimum temperature anomalies.

Other phenomena

It was the cloudiest December in Canberra since 1992, with only 8.3 hours per day of sunshine, which is below the historical average of 9.4 hours per day. One fog was observed (average 1 fog) during the month. Canberra's average wind run of 167.1 km per day was well below the historical average of 224.1 km per day. This is the lowest December wind run average for 15 years. Two strong winds were recorded during the month (average 3).

Canberra Airport recorded 5thunderstorms during December (historical average 4), with hail reported on the 27th. The average air pressure of 1013.8 hPa was higher than the historical average of 1011.2 hPa. Canberra Airport recorded 180.4 mm of evaporation during December, below the historical average of 255.8 mm.

Further information

Shannon Symons
Climate Officer
NSW Climate Services Centre
Bureau of Meteorology
Phone (02) 9296 1555
Email reqnsw@bom.gov.au

Extremes

Hottest day
Highest temperature
35.5°C at Tidbinbilla Nature Reserve on the 30th
Warmest days on average
Highest mean daily maximum temperature
25.1°C at Canberra Airport
25.1°C at Tuggeranong (Isabella Plains) AWS
Coolest days on average
Lowest mean daily maximum temperature
15.8°C at Mount Ginini AWS
Coldest day
Lowest daily maximum temperature
12.0°C at Mount Ginini AWS on the 1st
Coldest night
Lowest temperature
1.0°C at Mount Ginini AWS on the 18th
Coolest nights on average
Lowest mean daily minimum temperature
7.0°C at Mount Ginini AWS
Warmest nights on average
Highest mean daily minimum temperature
13.3°C at Canberra Airport
Warmest night
Highest daily minimum temperature
19.9°C at Canberra Airport on the 22nd
Wettest overall
Highest total rainfall

209.6 mm at Mount Ginini AWS
158.0 mm at Canberra (Stirling (College))

Wettest day
Highest daily rainfall
58.0 mm at Sullivan Creek (Southwell) on the 1st
54.8 mm at Mount Ginini AWS on the 22nd

Driest Overall
Lowest total rainfall

92.2 mm at Gordon (Bore)
Highest wind gust
76 km/h at Canberra Airport on the 22nd

Summaries

Summary statistics for December 2007
Maximum temperatures
for December
(°C)
Minimum temperatures
for December
(°C)
Rainfall
for December
(millimetres)
Mean for
December
2007
Diff
from
normal
Highest for
December
2007
Mean for
December
2007
Diff
from
normal
Lowest for
December
2007
Total for
December
2007
Normal
for
December
Rank of
December
2007
Fraction of
December
normal
Sthn Tablelands Gburn-Monaro (district 70)
Canberra Airport 25.1 −1.0 35.0 30th 13.3 +2.0 7.5 18th 100.6 52.5 high 192%
Mount Ginini AWS (elev 1760 m)* 15.8 24.0 29th 7.0 1.0 18th 209.6
Tuggeranong 25.1 35.0 30th 12.6 6.8 18th 98.0

* new station, no historic averages available


Notes

This statement has been prepared based on information available at 9 am on Thursday 3 January 2008. Some checks have been made on the data, but it is possible that results will change as new information becomes available.

A note about deciles: Deciles are used to give an element (in this case rainfall or temperature) a ranking. Deciles are calculated by arranging the totals in ascending order (from lowest to highest) then splitting them into 10 equal groups (thus the groups are called deciles). The first group would be in decile range one, the second group in decile range two, etc up to the highest annual totals (highest 10 per cent) being in decile range 10.

1Averages: Averages are based on the period 1961 to 1990 which is a convention of the World Meteorological Organisation

Normals are long-term averages 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 for temperature and less than 30 years of record for rainfall, as they cannot then be calculated reliably.

Further information

Shannon Symons
Climate Officer
NSW Climate Services Centre
Bureau of Meteorology
Phone (02) 9296 1555
Email reqnsw@bom.gov.au