ACT in August 2011: Winter ends with warm days and little frost

  • Third warmest August on record for maximum temperatures
  • Slightly above average minimum temperatures
  • Above average rainfall
  • Fewest frost days on record

Rainfall

Canberra Airport recorded 52 mm of rain during August, slightly above the historical average of 46.2 mm, following well below average rainfall during June and July. There were ten rain days during the month, close to average for August, primarily due to cold fronts during the second and third weeks of the month. The majority of the rain fell on the 18th, as a cold front caused 34.2 mm of rain at Canberra Airport and up to 61.8 mm at Mt Ginini AWS, as well as the wettest August day in 68 years of record at Tharwa General Store.

Some sites had their highest August daily rainfall on record.

Temperature

The average maximum temperature at Canberra Airport during August was 16 °C, 3 °C above the historical average of 13 °C, the third warmest August on record for maximum temperatures. Temperatures were particularly warm at the start and end of the month, with temperatures as high as 21.3 °C on the 3rd and nine consecutive days above 15 °C between the 23rd and 31st. Only one day dropped below 10 °C during the month, at 9.5 °C on the 18th, well below the average of 4 days.

The average minimum temperature was 1.2 °C during August, slightly above the historical average of 1.0 °C. There were eleven nights below 0 °C during the month, slightly below the August average of 13 days, reaching -3.3 °C on the 10th. The warmest period was between the 16th and 21st, where rain and cloudy conditions kept temperatures above 3 °C for six consecutive nights. Mean temperatures were consequently 1.6 °C above the historical average of 7 °C.

Wind

Afternoon winds were generally northwesterly during August, with 71% of 3pm winds between NNW and WNW, above the historial average of 40-50%. There were no strong wind days at Canberra Aiport during August, with a maximum wind gust of 52 km/hr on the 18th.

Other phenomena

Canberra Airport recorded an average of 6.4 hours of sunshine during August, below the historical average of 7 hours, with no thunderstorms reported in the ACT. There were only six frost days at Canberra during the month compared to the average of 18 days, the fewest on record for August following 7 days in August 1945.

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Extremes in August 2011
Hottest day 21.3 °C at Canberra Airport on the 3rd
Warmest days on average 16.0 °C at Canberra Airport
Coolest days on average 6.7 °C at Mount Ginini AWS
Coldest day -0.3 °C at Mount Ginini AWS on the 9th
Coldest night -5.0 °C at Mount Ginini AWS on the 9th
Coolest nights on average 0.0 °C at Mount Ginini AWS
Warmest nights on average 1.9 °C at Tuggeranong (Isabella Plains) AWS
Warmest night 7.6 °C at Tuggeranong (Isabella Plains) AWS on the 6th
Warmest on average overall 8.9 °C at Tuggeranong (Isabella Plains) AWS
Coolest on average overall 3.3 °C at Mount Ginini AWS
Wettest overall 106.8 mm at Mount Ginini AWS
Wettest day 61.8 mm at Mount Ginini AWS on the 18th
Highest wind gust 67 km/h at Mount Ginini AWS on the 19th

Record highest August daily rainfall
Highest daily rainfall
in August 2011 (mm)
Previous wettest
for August
Years of
record
Tharwa General Store 50.6 on the 18th 42.4 on the 24th in 2003 68



Summary statistics for August 2011
Maximum temperatures
for August
(°C)
Minimum temperatures
for August
(°C)
Rainfall
for August
(millimetres)
Mean for
August
2011
Diff
from
average
Highest for
August
2011
Mean for
August
2011
Diff
from
average
Lowest for
August
2011
Total for
August
2011
Average
for
August
Rank of
August
2011
Fraction of
August
average
Canberra Airport 16.0 +3.0 21.3 3rd 1.2 +0.2 -3.3 10th 52.0 46.2 average 113%
Mount Ginini AWS 6.7   13.9 24th 0.0   -5.0 9th 106.8
Tuggeranong (Isabella Plains) AWS 15.8   21.2 26th 1.9   -2.7 25th 62.2

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 Monthly 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