FYI: Monthly Climate Summary for Canberra - April 2009 [SEC=UNCLASSIFIED

Subject: FYI: Monthly Climate Summary for Canberra - April 2009 [SEC=UNCLASSIFIED]
Date: Tue, 5 May 2009 12:05:52 +1000

With climate being such an important factor in our bird population, the following is provided for the information of subscribers (and as an addition to the annual summary provided in the Annual Bird Report):

Canberra has wettest April since 1990

·        Above average rainfall, the highest for April since 1990
·        Close to average maximum temperatures
·        Well above average minimum temperatures, highest for 11 years
·        Coldest consecutive 5 days in April since 1952


Following very dry conditions in February and March, some welcome rain was recorded over the ACT during April. Canberra Airport recorded its wettest April since 1990 with a total of 71 mm, compared to the historic average1 of 46 mm. It is also the wettest Autumn month in Canberra since May 1995, which goes against a recent trend of dry Autumns in the ACT. Tuggeranong recorded considerably higher rainfall with a total of 99 mm for the month and Mount Ginini in the Brindabella Ranges recorded 140 mm. There were 10 rain days at Canberra Airport during the month compared to the historic average of 7 rain days. Active low pressure troughs on the 3rd, 14th and 26th were responsible for most of the rain.

Mount Ginini had the Territory's highest April total of 140 mm while Kingston recorded the lowest total of only 67 mm. The wettest day was 42.0 mm at Deakin West on the 14th caused by a low pressure trough.


Daytime temperatures were cool to mild in the ACT during April. Canberra Airport recorded an average maximum temperature of 19.6 °C, which is 0.4 °C below the historical average of 20.0 °C. Daily maximum temperatures reached the low 20's for most of the month except during the last week when a cool change brought much colder weather. Canberra Airport recorded 5 consecutive days (25th to 29th) with a maximum temperature below 15 °C, the longest cold spell for April since 1952.

The below average daytime temperatures were partly due to prevailing S-SE winds, especially during the mornings and the partly cloudy, showery weather.

Overnight temperatures were quite mild. The average minimum temperature at Canberra Airport was 8.4 °C which is 1.8 °C above the historic average. This is the highest average minimum temperature for April since 1998. The minimum temperature on the warmest night was 15.1 °C both on the 1st and 2nd. The minimum temperature on the first 3 days of the month exceeded 14.5 °C, which has not occurred over 3 consecutive days in April since 1989.

Temperature extremes at Canberra Airport ranged from a high of 28.6 °C on the 3rd to an overnight low of 1.8 °C on the 29th. The lowest temperature in the ACT was -5.0 °C at Mount Ginini AWS on the 29th following a strong cold front.


S-SE winds prevailed over the ACT during April for 50% of the time during the mornings which is more than twice the normal frequency from this direction. There were 2 windy days recorded during the month associated with westerly winds. The highest wind gust was 96 km/h from NNW at Canberra Airport on the 24th associated with the passage of a cold front, the strongest winds in April since 1993. The more exposed mountains to the SW of the city recorded wind gusts of 100 km/h from the northwest at Mount Ginini AWS on the 25th.

Other phenomena

Cloudy days prevailed in the ACT during April. A total of 14 cloudy days exceeded the historic average of 9 cloudy days. Sunshine averaged 7.1 hours per day, a little below the historic April average of 7.3 hours per day. There were 3 thunderstorms reported at Canberra Airport during the month, on the 3rd, 11th and 14th. Widespread raised dust on the 15th reduced visibility to only 4 km over the ACT. The dust originated over western Victoria and southern NSW and was caused by the combination of strong westerly winds and persistent dry weather over southern inland NSW. At least 10 cm snow fell on the mountains to the SW of Canberra from 26th to the 28th following the passage of a cold front.********************************************************************** IMPORTANT: This e-mail is intended for the use of the addressee and may contain information that is confidential, commercially valuable or subject to legal or parliamentary privilege. If you are not the intended recipient you are notified that any review, re-transmission, disclosure, use or dissemination of this communication is strictly prohibited by several Commonwealth Acts of Parliament. If you have received this communication in error please notify the sender immediately and delete all copies of this transmission together with any attachments. **********************************************************************

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