ACT in winter 2011: Warmest winter days on record

  • Warmest maximum temperatures on record.
  • Below average rainfall
  • Below average minimum temperatures, coldest winter night since 1994 on July 29.

Rainfall

Canberra Airport recorded 86.0 mm of rain during winter, below the historical average of 127.8 mm. Rainfall was particularly low during June where only 8.8 mm fell, with below average falls again in July, but slightly above average rainfall during August. The majority of the rain fell during a cold front which crossed the state on August 18, bringing 34.2 mm at Canberra Airport and up to 61.8 mm at Mt Ginini AWS.

Temperature

Canberra experienced its warmest winter on record during 2011, with an average maximum temperature of 14.0 °C at Canberra Airport, 1.8 °C above the historical average of 12.2 °C and 0.3 °C above the previous record (set in 2005). Maximum temperatures were above average throughout the season but particularly high during August, associated with the generally decreased rainfall and cloud cover during the season. There were 31 days with maximum temperatures above 15 °C during winter, the highest on record, of which five reached 20 °C. Daily maximums peaked at 21.3 °C on August 3, the warmest winter day since 2007. Only 8 days during winter reached temperatures cooler than 10 °C, well below the historical average of 17 days, with the coldest day reaching just 7 °C on July 24.

Minimum temperatures were closer to average at Canberra Airport at 0.4 °C, 0.2 °C below the historical average of 0.6 °C. This was primarily due to cool nights and clear conditions in both June and July, with closer to average minimums during August. Temperatures were particularly cold during July, reaching just -8 °C on July 29, the coldest winter night since 9 August 1994. Only 7 nights during winter were at least 5 °C, half the winter average and the fewest warm nights since 1977; however, only 42 nights had minimums below 0 °C, average for winter.

Mean temperatures were consequently 7.2 °C during winter, above the historical average of 6.4 °C for the 14th consecutive year.

Wind

Winds were predominantly northwesterly during winter, with 59% of 3pm winds between NNW and WNW, contributing to the warm conditions during the season. Only two strong wind days were reported, both during July, with a maximum wind gust at Canberra Airport of 83 km/hr on July 5.

Other phenomena

Canberra Airport recorded an average of 5.9 hours of sunshine during winter, close to the historical average of 6 hours. No thunderstorms were reported anywhere in the ACT during the season.

Further information

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Extremes in winter 2011
Hottest day 21.3 °C at Canberra Airport on 3 Aug
Warmest days on average 14.0 °C at Canberra Airport
Coolest days on average 3.7 °C at Mount Ginini AWS
Coldest day -2.1 °C at Mount Ginini AWS on 5 Jul
Coldest night -8.2 °C at Tuggeranong (Isabella Plains) AWS on 29 Jul
Coolest nights on average -1.6 °C at Mount Ginini AWS
Warmest nights on average 1.0 °C at Tuggeranong (Isabella Plains) AWS
Warmest night 8.1 °C at Tuggeranong (Isabella Plains) AWS on 14 Jun
Warmest on average overall 7.4 °C at Tuggeranong (Isabella Plains) AWS
Coolest on average overall 1.1 °C at Mount Ginini AWS
Wettest overall 227.4 mm at Mount Ginini AWS
Wettest day 61.8 mm at Mount Ginini AWS on 18 Aug
Highest wind gust 106 km/h at Mount Ginini AWS on 5 Jul

Summary statistics for winter 2011
Maximum temperatures
for winter
(°C)
Minimum temperatures
for winter
(°C)
Rainfall
for winter
(millimetres)
Mean for
winter
2011
Diff
from
average
Highest for
winter
2011
Mean for
winter
2011
Diff
from
average
Lowest for
winter
2011
Total for
winter
2011
Average
for
winter
Rank of
winter
2011
Fraction of
winter
average
Canberra Airport 14.0 +1.8 21.3 3 Aug 0.4 -0.2 -8.0 29 Jul 86.0 127.9 low 67%
Mount Ginini AWS 3.7   13.9 24 Aug -1.6   -6.6 15 Jul 227.4
Tuggeranong (Isabella Plains) AWS 13.8   21.2 26 Aug 1.0   -8.2 29 Jul 110.8

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 10 am on Thursday 1 September 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