Canberra in summer 2011-12: Coldest summer in over a decade

  • Above average rainfall
  • Below average temperatures, coldest since 1995/6.
  • Fewest hot days since 1991/2.
  • Coldest summer night since December 1964.

Rainfall

Canberra recorded 202.4 mm of rain during summer, above the historical average of 168.7 mm. This was the 14th wettest summer on record for Canberra, although substantially drier than the summer of 2010-11 (375.2 mm). Most of the rain fell during February, which recorded more than twice the historical average rainfall, while both December and January were close to average. The rain fell over 33 rain days, well above the historical average of 22 rain days, but slightly fwere than 2010-11 (34 wet days). The wettest day reached 29.8 mm on the 29th of February associated with a low pressure trough, with the wettest day anywhere in the ACT reaching 52 mm at Tharwa General Store on January 21st, associated with thunderstorm activity.

Temperature

The average maximum temperature at Canberra Airport during summer was 25.4 °C, 1.7 °C below the historical average. This is the second consecutive cool summer for Canberra, and the coolest summer since an average of 24.7 °C in summer 1995/6. Temperatures were below average throughout the season, associated with above average cloud cover and a lack of warm days, with only 12 days reaching 30 °C, less than half the historical average (26 days) and the fewest since 1991/2. No days reached 35 °C during the season (average 5 days) for the first time since 2001/2, with the hottest day reaching 34.7 °C on January 3rd.

The average minimum temperature during summer was 12.0 °C, 0.5 °C below the historical average of 12.5 °C. This is the first summer with below average minimum temperatures at Canberra Airport since 11.9 °C in summer 1999/2000. Nights were coolest during December, which was the coolest since 1995, while January was the coolest since 2000. Temperatures were particularly cold on the 12th and 13th of January, with two consecutive nights below 5 °C, reaching 1.6 °C on the 12th. This was the coldest January night on record for Canberra, and the coldest summer night since 1.1 °C was recorded on the 18th of December 1964.

The mean summer temperature for Canberra Airport was consequently 18.7 °C, the coldest summer for Canberra since 1995/6.

Other phenomena

The prevailing wind direction during summer was between N and W, forming 45% of 3pm winds, with 42% of 3pm winds between NNE and ESE. This is a higher frequency of easterly winds than typical for summer, with N-W winds typically forming 60% of summer winds, contributing to the cool, cloudy conditions during the season. The strongest wind gust was on January 11, reaching 72 km/hr at Canberra Airport, with 70 km/hr recorded on January 30. There were 33 thunderstorms anywhere in the ACT region, above normal for summer.

Further information

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Extremes in summer 2011-12
Hottest day 34.7 °C at Canberra Airport on 3 Jan 2012
Warmest days on average 25.4 °C at Canberra Airport
Coolest days on average 16.3 °C at Mount Ginini AWS
Coldest day 3.8 °C at Mount Ginini AWS on 11 Jan 2012
Coldest night -3.0 °C at Mount Ginini AWS on 5 Dec 2011
Coolest nights on average 7.2 °C at Mount Ginini AWS
Warmest nights on average 12.5 °C at Tuggeranong (Isabella Plains) AWS
Warmest night 19.0 °C at Canberra Airport on 28 Feb 2012
Warmest on average overall 18.7 °C at Canberra Airport
18.7 °C at Tuggeranong (Isabella Plains) AWS
Coolest on average overall 11.8 °C at Mount Ginini AWS
Wettest overall 513.8 mm at Mount Ginini AWS
Wettest day 52.0 mm at Tharwa General Store on 21 Jan 2012
Highest wind gust 81 km/h at Mount Ginini AWS on 30 Jan 2012

Summary statistics for summer 2011-12
Maximum temperatures
for summer
(°C)
Minimum temperatures
for summer
(°C)
Rainfall
for summer
(millimetres)
Mean for
summer
2011-12
Diff
from
average
Highest for
summer
2011-12
Mean for
summer
2011-12
Diff
from
average
Lowest for
summer
2011-12
Total for
summer
2011-12
Average
for
summer
Rank of
summer
2011-12
Fraction of
summer
average
Canberra Airport 25.4 -1.7 34.7 3 Jan 2012 12.0 -0.5 1.6 12 Jan 2012 237.8 168.7 high 141%
Mount Ginini AWS 16.3   25.0 3 Jan 2012 7.2   -3.0 5 Dec 2011 513.8
Tuggeranong (Isabella Plains) AWS 25.0   33.9 3 Jan 2012 12.5   3.8 12 Jan 2012 371.8

Notes

As of March 2010, the official station for Canberra is 70351 'Canberra Airport'. Averages from the previous site, 70014 Canberra Airport Comparison, are used for comparisons (all years of record).

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 11 am on Thursday 1 March 2012. 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