FYI: Seasonal Climate Summary for Canberra - Winter 2009

[Matthew Frawley <>]

The following is provided for the information of subscribers (and as an addition to the annual summary provided in the Annual Bird Report): http://www.bom.gov.au/climate/current/season/act/summary.shtml

A mild winter for the ACT

• The 17th consecutive winter with above average maximum temperatures
• 3rd highest mean minimum temperatures on record
• Close to average rainfall and sunshine hours

Rainfall

Canberra Airport recorded a total winter rainfall of 103.2mm, slightly below the historical winter average of 128.3 mm. It is the 4th consecutive winter with below average rainfall. There was a total of 36 rain days during winter, the highest number since winter 1990 (when 37 days). The historic average for winter is 31 rain days.

The highest winter total in the ACT was 308.2 mm at Corin Dam while the highest in Canberra suburbs was 142.0 mm at Sullivan Creek (Southwell). The lowest totals tended to be in southern suburbs, Tralee recording the lowest with 72.8 mm.

Temperatures

The average maximum temperature at Canberra Airport was 13.2°C, which is 1°C above the historical average of 12.2°C and the 10th warmest in the 71 year record. Canberra has now experienced 17 consecutive winters with above average maximum temperatures. All three winter months experienced above average daytime and night-time temperatures but this was especially so in July and August.

The average minimum temperature for winter for Canberra Airport was 2.3°C which is 1.7°C above the historical average of 0.6°C. This is the third highest average minimum temperature on record for winter and the warmest since 2.8°C in winter 1991. Very mild nights occurred during the last week of August including a record high minimum of 12.0 °C on 24 August.

The extreme temperatures in the ACT during winter ranged from a high of 19.1 °C at Tuggeranong AWS on 23 August to a low of -8.5 °C at Mount Ginini AWS on 11 June, and in suburban Canberra, -6.0 °C at Tuggeranong AWS also on 11 June.

Wind

The prevailing winter winds at Canberra Airport were close to the long term averages. During the mornings (9am) the prevailing wind was from the NW for 25% of the time, compared to the expected 21%. During the afternoons (3pm) the prevailing wind direction was W-NW, accounting for 67% of the observations, which is close to what is expected for this season. Six days of strong winds were recorded, below the average of 9 for winter. The highest wind gust during winter was 109 km/h at Mount Ginini AWS and 89 km/h at Canberra Airport, both on 25 August.

Other phenomena

There were 2 thunderstorms (on 11 and 29 August) and 1 hail day (11 August) reported at Canberra airport during winter, both close to normal frequencies. Bright sunshine averaged 6.0 hours per day which is normal for winter. There were 38 frosts, well below the winter average of 58, and 17 fogs, close to the average of 20. No official reports of snow occurred at Canberra Airport although moderate snowfalls occurred at times on the Brindabella Ranges SW of Canberra during June and early July.