Wednesday, 1 June 2011 - Seasonal Climate Summary for Sydney - Greater Sydney - Product code IDCKGC25L0

Sydney in autumn 2011: Wettest Autumn since 2003

• Wettest Autumn since 2003
• Wettest Autumn day since 1998
• Above average temperatures at Sydney Observatory Hill, below average in the west

Extremes Records Summaries Important notes the top

Rainfall

Sydney Observatory Hill recorded 533.4 mm of rain during Autumn, well above the historical average of 376.8 mm and the wettest Autumn since 672.8 mm fell in 2003. All three months during the season had above average rainfall, with both March and April the wettest in more than ten years.

The most significant rainfall event occurred during March as a complex low pressure system developed in a trough off the coast, with daily totals of up to 178 mm at St Ives on the 20th and record-breaking daily falls in the Northern Beaches area. Rainfall reached 99.4 mm at Observatory Hill, the wettest Autumn day since May 1998. Rainfall over 50 mm was also recorded on April 16 and May 31, above the historical average of 1-2 50 mm days and the largest number of heavy days since Autumn 2001.

Temperature

The average maximum temperature at Sydney Observatory Hill during Autumn was 22.7 °C, 0.5 °C above the historical average of 22.2 °C, with most of western Sydney recording below average temperatures. Temperatures were particularly warm during March, with several days above 30 °C during the first part of the month, while conditions were closer to average in April and May.

Minimum temperatures were also below average in the west but above average nearer the coast, with average minimums of 14.9 °C at Observatory Hill compared to the historical average of 14.6 °C. This was associated with lingering warm sea surface temperatures in the NSW region during the first part of the season as the La Niña event decayed in the Pacific, although temperatures were cooler than experienced in the autumns of 2009 and 2010.

Wind

Winds were predominantly southerly during Autumn, with 58% of 3pm winds between SE and SW, slightly above average for Autumn. A total of 13 strong wind days were reported during the season, particularly during May, which is slightly above average for Autumn.

Other phenomena

Sunshine averaged 6.1 hours at Sydney Airport during Autumn, below the historical average of 6.4 hours and the lowest sunshine since 6.0 hours in Autumn 2001, with particularly low sunshine during March. Only one thunderstorm was reported at Sydney Airport during Autumn, below the historical average of 3-4 storms.

Extremes Records Summaries Important notes the top

Extremes Records Summaries Important notes the top