Canberra in summer 2010-11: Second wettest summer on record

  • 2nd wettest summer on record, wettest in 63 years.
  • Wettest summer day since 1995.
  • Above average minimum temperatures.

Rainfall

Canberra Airport recorded 375.2mm of rainfall during summer 2010/11, double the historical average of 168.7mm and the second wettest summer on record following summer 1947/8 (476.9mm). Throughout the ACT, seasonal rainfall was as high as 635.6mm at Mt Ginini, with Tharwa General Store experiencing its wettest summer on record. The majority of the rain fell during December, which was the second wettest on record in Canberra, with above average rainfall in February but below average falls in January. The rain fell over 30 rain days, well above the historical average of 22 days.

Five days above 25mm were recorded during the season, the second largest number of heavy rain events on record following 6 days in summer 1947/1948. The heaviest rainfall at Canberra Airport was 87mm on December 3rd, the wettest December day on record and the wettest summer day since 21 January 1995, while Tuggeranong recorded daily rainfall of 93mm on December 9th. The heaviest rain day anywhere in Canberra was 102.2mm at Mt Ginini on February 3rd during a strong rainfall event across southern NSW.

Some sites had their highest total summer rainfall on record.

Temperature

Maximum temperatures in Canberra were slightly below average during summer at 26.8 °C compared to the historical average of 27.1 °C. The low average maximums were a consequence of cool temperatures during both December and February, with slightly warmer temperatures during January. The warmest days were the 31st of January and the 1st of February, reaching 37.5 °C and 37.1 °C respectively, with only three days exceeding 35 °C during the season, the lowest frequency in ten years.

In comparison, Canberra experienced above average minimum temperatures during summer at 13.8 °C, 1.3 °C higher than the historical average of 12.5 °C. This is the 11th consecutive summer with above average minimum temperatures in Canberra. All three months experienced above average night time temperatures, warmest during January. Mean temperatures were consequently 0.6 °C above average during summer for the ninth consecutive year.

Wind

Canberra experienced predominantly northwesterly winds during summer, with 68% of 3pm winds from a northerly to westerly direction, typical for summer. Only two strong wind days were reported at Canberra Airport during the season, well below the historical average of 5 days, with a maximum wind gust of 91km/hr at Mt Ginini on February 19.

Other phenomena

Canberra recorded an average of 8 hours of sunshine per day during the season, below the historical average of 9.3 hours and the lowest sunshine since 1992. Fourteen thunderstorms were reported at Canberra Airport during summer 2010/11, above the historical average of 12, with 25 storms reported throughout the ACT region. Hail was associated with three events on December 2, December 8 and January 5, the last associated with golf-ball sized hail in Canberra.

Further information

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Extremes in summer 2010-11
Hottest day 37.6 °C at Tuggeranong (Isabella Plains) AWS on 31 Jan 2011
Warmest days on average 26.8 °C at Canberra Airport
Coolest days on average 17.9 °C at Mount Ginini AWS
Coldest day 5.2 °C at Mount Ginini AWS on 20 Dec 2010
Coldest night -1.3 °C at Mount Ginini AWS on 20 Dec 2010
Coolest nights on average 8.7 °C at Mount Ginini AWS
Warmest nights on average 14.6 °C at Tuggeranong (Isabella Plains) AWS
Warmest night 23.0 °C at Tuggeranong (Isabella Plains) AWS on 2 Feb 2011
Warmest on average overall 20.7 °C at Tuggeranong (Isabella Plains) AWS
Coolest on average overall 13.3 °C at Mount Ginini AWS
Wettest overall 635.6 mm at Mount Ginini AWS
Wettest day 102.2 mm at Mount Ginini AWS on 3 Feb 2011
Highest wind gust 91 km/h at Mount Ginini AWS on 19 Feb 2011

Record highest total summer rainfall
Total rainfall
for summer 2010-11 (mm)
Previous wettest
for summer
Years of
record
Average for
summer
Tharwa General Store 462.8 320.9 in 1940 56 171.6



Summary statistics for summer 2010-11
Maximum temperatures
for summer
(°C)
Minimum temperatures
for summer
(°C)
Rainfall
for summer
(millimetres)
Mean for
summer
2010-11
Diff
from
average
Highest for
summer
2010-11
Mean for
summer
2010-11
Diff
from
average
Lowest for
summer
2010-11
Total for
summer
2010-11
Average
for
summer
Rank of
summer
2010-11
Fraction of
summer
average
Canberra Airport 26.8 -0.3 37.5 31 Jan 2011 13.8 +1.3 4.7 19 Dec 2010 375.2 168.7 v high 222%
Mount Ginini AWS 17.9   28.0 31 Jan 2011 8.7   -1.3 20 Dec 2010 635.6
Tuggeranong (Isabella Plains) AWS 26.7   37.6 31 Jan 2011 14.6   5.4 19 Dec 2010 516.0

Notes

A Seasonal Climate Summary is prepared to list the main features of the weather in ACT Monthly Summary 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 10 am on Tuesday 1 March 2011. 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