Tuesday, 4 October 2011 - Monthly Climate Summary for ACT Monthly Summary - Product code IDCKGC15R0

ACT in September 2011: Hot days and cold nights in Canberra

• Below average rain.
• 4th warmest September on record for maximum temperatures.
• Below average minimums, coolest since 1994.
• 3rd warmest September day on record, and 5th coolest September night.

Extremes Records Summaries Important notes the top

Rainfall

Canberra Airport recorded 32.6 mm of rain during September, below the historical average of 52 mm. The rain fell over 9 days, close to average for September, with a maximum daily fall of 10.2 mm on the 29th, reaching 25.2 mm at Mt Ginini on the same day. Rain exceeding 5 mm was also recorded on the 7th and 25th of the month, with clear conditions dominating the rest of September.

Temperature

Maximum temperatures were very warm during September at 18.2 °C, 2.0 °C above the historical average of 16.2 °C. This was the 4th warmest September on record for maximum temperatures, and the warmest since September 2006 (19.4 °C). The warm days were associated with generally clear conditions and above average sunshine during the month. Temperatures were particularly warm between the 17th and 19th when temperatures exceeded 24 °C for three consecutive days, peaking at 27.1 °C on the 19th, the 3rd warmest September day on record. Temperatures again reached 25.3 °C on the 23rd, with the second highest number of days above 24 °C on record for September following five days in 1987. The coolest temperature during the month was 12.6 °C, only exceeded during September 2007 when no days dropped below 12.7 °C.

In comparison, the average minimum temperature during September was 1.9 °C, 1.4 °C below the historical average of 3.3 °C. This was the coolest September since 1994, associated with the generally clear conditions during the month. Only one night during September exceeded 10 °C, with 13 nights below 0 °C and 7 below -2 °C, double the historical average and the most -2 °C nights since 1971. Temperatures were particularly low between the 10th and 14th, with five consecutive nights below -1 °C, the longest cold spell on record for September. The minimum temperature was just -5.2 °C on the 10th, the 5th coldest September night on record and the coldest since -6.4 °C on September 10 1982.

The mean daily temperature was 10.1 °C, 0.3 °C above the historical average.

Wind

Winds were generally northwesterly during September, with 75% of 3pm winds between WNW and NNW, normal for September. No strong wind days were reported at the Airport during the month, with a maximum wind gust of 83 km/hr on the 19th. The strongest wind gust anywhere in the ACT was 107 km/hr at Mt Ginini on the 20th.

Other phenomena

Canberra Airport reported 7.9 hours of sunshine during September, slightly above the historical average of 7.7 hours. There were no thunderstorms reported at the Airport, with five reported in the ACT. Six frost days were reported during the month, below the September average of 13 frosts.

Extremes Records Summaries Important notes the top

Extremes Records Summaries Important notes the top