Monday, 3 June 2013 - Seasonal Climate Summary for Sydney  - Product code IDCKGC25L0

Sydney in autumn 2013: A warm autumn for Sydney

• Equal-third-warmest autumn for mean maximum temperatures, fewest cold days on record
• Most heavy rain days since 2003; driest autumn spell on record
• Close to average minimum temperatures
• Well above average sunshine, few cloudy days

Extremes Records Summaries Important notes the top

Rainfall

Sydney Observatory Hill recorded 375.6 mm of rain during autumn, close to the historical average of 377.5 mm, with autumn totals close to normal across the city. The rain fell over 34 days, close to the autumn average of 39 days, of which eight recorded at least 25 mm (average 4 days), the most since 2003. This included a 3-day total of 107.2 mm to 9am on 5 April during a period of easterly flow, while East Coast Lows produced 64.8 mm between 2 am and 2 pm on 20 April and a 3-day total of 77.8 mm to 9am on 25 May.

Autumn also featured several dry, clear spells. Notably, only 0.2 mm of rain was recorded in the four weeks between 24 April and 22 May. This is the driest such period on record for autumn, although similar spells occurred in 2012 (0.4 mm from 26 April - 24 May) and 1973 (0.3 mm from 3 May - 1 June).

Temperature

Sydney Observatory Hill recorded an average maximum temperature of 23.9 °C during autumn, 1.7 °C above the historical average. This is the equal-third-warmest autumn on record and the warmest autumn since 2007; the last autumn with below average maximum temperatures at Sydney Observatory Hill was in 1972. Temperatures were above average across the city, associated with several clear, sunny spells and a lack of cold days.

Only six days had maximum temperatures below 20 °C during autumn, the fewest cold days on record (average 26 days); this is substantially fewer than the previous record of 9 days, set in 1958. There were also 35 days above 25 °C, the equal-fifth-highest frequency and almost double the average of 20 days, although only three days exceeded 30 °C (average 2 days). There were several notable mild spells including 2-28 March and 21 April - 16 May, while temperatures reached 33.5 °C on 28 March, the latest such warm day since 1986.

The average minimum temperature at Sydney Observatory Hill was 15.3 °C, 0.7 °C above the historical average, with slightly below average temperatures at sites in western Sydney. Nights were warmer than average during March but closer to normal in April and May; only four nights dropped below 10 °C during the season (average 9-10 nights) while 14 reached at least 20 °C, the most since 2007 (average 4-5 nights). The mean temperature during autumn was consequently 19.6 °C, 1.2 °C above the historical average.

Other phenomena

Sydney Airport recorded an average of 7.5 hours of bright sunshine during autumn, well above the historical average of 6.7 hours and the sunniest autumn since 2008. There were 22 cloudy days, well below the historical average of 34 days and the fewest since 22 days in 2008; the only other autumn so clear was in 1991 (21 cloudy days). Three thunderstorms were reported during the season, with heavy fog on 28 and 29 April.

The prevailing wind direction was southerly, with 49% of 3pm winds between SE and SW, close to normal for autumn, while 31% of 3pm winds were NNE-ENE. Only 11% of 3pm winds were between N and W, below average for autumn (15%). There were 15 strong wind days reported at the airport, with a maximum wind gust of 76 km/h on 19 April.

Extremes Records Summaries Important notes the top

Extremes Records Summaries Important notes the top