Monday, 1 June 2009 - Seasonal Climate Summary for Canberra rainfall extremes - Product code IDCKGC25x0

Canberra has mild, dry autumn

Summary 

Canberra and the ACT had a very mild autumn with below average rainfall. Autumn ended on a very dry note with only 2.4 mm of rain during May.

Main points 

  • 9th consecutive autumn with below average rainfall.
  • 13th consecutive autumn with above average maximum temperatures.
  • Below average rainfall
  • Mild days with above average maximum temperatures
  • Mild nights with above average minimum temperatures
  • Sunny autumn with above average sunshine hours

An archive of previous seasonal summaries for Canberra rainfall extremes is also available, as are summaries for other states and many other climate summaries and diagnostics.

Rainfall

The total autumn rainfall of 85.2 mm at Canberra Airport was well below the historical autumn average1 of 140.7  mm. Nearly all of the season's rainfall occurred during April with March and May very dry months. Autumn in Canberra ranked as the 18th driest out of 70 years of record. This is now the 9th consecutive autumn with below average rainfall in the ACT. There were 17 rain days during autumn, below the historic average of 22 rain days. A third of autumn's total rainfall occurred on one day on 14 April when a low pressure trough from the west caused widespread showers and storms over the ACT. However, all other falls during autumn were light and scattered.

The wettest location in the ACT during autumn was at Mount Ginini AWS with a total of 184.8 mm. In the Canberra suburban area the highest was 132.2 mm at Canberra Farrer Pluvio. The driest location was at Chifley with a total of 84.6 mm.

Temperatures

Mild days prevailed in the ACT during autumn. The average1 maximum temperature for autumn at Canberra Airport was 20.9°C, which is 0.9°C above the historical autumn average of 20.0°C. This is the 11th warmest autumn out of 70 years of record in Canberra. It is also the 13th consecutive autumn with above average maximum temperatures in the ACT.

The warm conditions were due to an abundance of sunny days and few significant cool changes. Overnight temperatures were above average with Canberra Airport recording an average minimum temperature of 8.1°C, which is 1.3°C above the historical autumn average of 6.8°C.

Temperature extremes at Canberra Airport ranged from a high of 31.9°C on 24th of March and a low of −0.5°C on 10th of May. The lowest temperature in the ACT during autumn was −5.0°C at Mount Ginini AWS on the 29th following a strong cold front. The lowest in the Canberra metropolitan area was −1.1°C at Tuggeranong on 17 May.

Wind

S-SE winds prevailed over the ACT during Autumn for 48% of the time during mornings. Several days of strong winds were recorded during autumn. The strongest wind gust of 96 km/h from the NNW was recorded at Canberra Airport on 24th April associated with the passage of a cold front. The more exposed mountains to the SW of the city recorded wind gusts of over 100 km/h from the northwest on the 25th (Mount Ginini).

Other phenomena

Sunshine averaged 7.5 hours during autumn which was above the historical average of 7.1 hours per day. During autumn three thunderstorms were reported at Canberra Airport from March to April with none reported in May. On the 15th of April widespread raised dust was reported reducing visibility to only 4 km over the ACT. Snow also fell later in April, with at least 10 cm of snow falling on the mountains to the SW of Canberra between the 26th and 28th and was associated with the passage of a cold front. During May, there were 9 days when fog was observed at the airport or in patches within immediate vicinity. The lowest visibility reported was 300 m at Canberra Airport on 1st of May.

Further information


NSW Climate Services Centre
Bureau of Meteorology
Phone (02) 9296 1555
Email climate.nsw@bom.gov.au

Extremes

Hottest day
Highest temperature
31.9°C at Canberra Airport on 24 Mar
Warmest days on average
Highest mean daily maximum temperature
20.9°C at Canberra Airport
Coolest days on average
Lowest mean daily maximum temperature
11.6°C at Mount Ginini AWS
20.8°C at Tuggeranong AWS
Coldest day
Lowest daily maximum temperature
12.9°C at Canberra Airport and Tuggeranong on 29 May
−1.7°C at Mount Ginini AWS on 26 Apr
Coldest night
Lowest temperature
−1.1°C at Tuggeranong AWS on 17 May
−5.0°C at Mount Ginini AWS on 29 Apr
Coolest nights on average
Lowest mean daily minimum temperature
3.6°C at Mount Ginini AWS
8.1°C at Canberra Airport
Warmest nights on average
Highest mean daily minimum temperature
8.2°C at Tuggeranong AWS
Warmest night
Highest daily minimum temperature
17.3°C at Tuggeranong AWS on 3 Mar
17.3°C at Tuggeranong AWS on 13 Mar
Wettest overall
Highest total rainfall
184.8 mm at Mount Ginini AWS
132.2 mm at Canberra Farrer Pluvio
Driest overall
Lowest total rainfall
84.6 mm at Chifley (Waldock Street)
Wettest day
Highest daily rainfall
42.6 mm at Canberra Farrer Pluvio on 18 Apr
39.8 mm at Bendora Dam on 5 Mar
Highest wind gust
100 km/h at Mount Ginini AWS on 25 Apr
96 km/h at Canberra Airport on 24 Apr

Records

Nil recorded


Summaries

This table is very wide and may not fit if printed.

Summary statistics for autumn 2009
Maximum temperatures
for autumn
(°C)
Minimum temperatures
for autumn
(°C)
Rainfall
for autumn
(millimetres)
Mean for
autumn
2009
Diff
from
average
Highest for
autumn
2009
Mean for
autumn
2009
Diff
from
average
Lowest for
autumn
2009
Total for
autumn
2009
Average
for
autumn
Rank of
autumn
2009
Fraction of
autumn
average
Canberra Airport 20.9 +0.9 31.9 24 Mar 8.1 +1.3 −0.5 7 May 85.2 140.7 low 61%
Mount Ginini AWS 11.6   21.0 24 Mar 3.6   −5.0 29 Apr 184.8
Tuggeranong 20.8 −0.4 31.7 24 Mar 8.2 +1.4 −1.1 17 May 112.2 81.2 average 138%

Notes

This statement has been prepared based on information available at 1 pm on Monday 1 June 2009. 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


NSW Climate Services Centre
Bureau of Meteorology
Phone (02) 9296 1555
Email climate.nsw@bom.gov.au