Monday, 3 September 2012 - Seasonal Climate Summary for Sydney - Product code IDCKGC25L0
Sydney in winter 2012: Warm, windy winter for Sydney
- Close to average rainfall across the city, but wettest June since 2007
- Days reached 29.4 °C on August 23, warmest winter day since 1995
- Two days with wind gusts above 100 km/hr, first time in winter since 1978
Wet June, but drier end to winter
Sydney Observatory Hill recorded 319.4 mm of rain during winter, close to the historical average of 310.6 mm, which fell over 33 rain days (average for winter).
Most of the rain fell during June, 244.2 mm, which was the wettest June in Sydney since 2007, a consequence of two East Coast Lows and a rain-bearing trough during the first half of the month. During the second ECL, daily falls reached 89.8 mm at Rose Bay on the 11th and 102.4 mm at Potts Hill on the 12th, with a 48-hour rainfall of 125.8 mm at Observatory Hill.
In comparison, both July and August recorded well below average rainfall in Sydney, the driest July-August period since 2009. While there were 17 days of rain (average 22), only two days reached 10 mm at Observatory Hill during this period, compared with 6 such days in June.
Warm days across the city
The average maximum temperature at Sydney Observatory Hill during winter was 18.4 °C, 1.4 °C above the historical average. Days were warmer than average across most of the city and throughout the season, with warmest conditions later in August when rainfall was low and skies clear.
Only seven days were 15 °C or cooler during the season (average 21), while 23 days recorded at least 20 °C (average 12). The warmest day was the 23rd of August, when temperatures reached 29.4 °C at Sydney Observatory Hill and 30 °C at Sydney Airport, in both cases the 4th warmest winter day on record.
The average minimum temperature at Sydney Observatory Hill was 9.3 °C, 0.5 °C above average, with temperatures slightly cooler than average in western Sydney but well above average at Sydney Airport. No nights fell below 5 °C during winter (average 3 nights), with the warmest night reaching 16.1 °C on August 23rd. In western Sydney, 13 nights dropped to 0 °C in Richmond, close to normal for winter (12 nights).
ECLs and fronts cause strong winds in the city
The prevailing wind direction at Sydney Airport was southerly, with 43% of 3pm winds SE-SW, normal for winter. There were 12 strong wind days during the winter, which is close to normal, with several significant wind events causing damage in the city. For more detail about individual events see the relevant Monthly Summary.
During an East Coast Low on 5-6 June, Sydney Airport recorded a maximum wind gust of 104 km/hr, reaching 117 km/hr at Port Botany. Mean winds remained above 50 km/hr for 15 hours, in addition to large waves and beach erosion.
Sydney also recorded very strong winds on the 10th and 11th of August, as a low pressure system developed offshore in the wake of a front. Gusts reached 106 km/hr at Sydney Airport and 115 km/hr at Port Botany, with wind speeds remaining above 50 km/hr for almost twelve hours, and 10-minute mean wind speeds as high as 80 km/hr.
Sydney Airport also recorded a wind gust of 89 km/hr during a thunderstorm on August 23rd, and gusts of up to 78 km/hr associated with a cold front on August 17th, causing further damage. The last time Sydney Airport had two days with wind gusts above 100 km/hr during winter was in 1978.
First thunderstorm at the airport since April
Sydney Airport recorded an average of 6.8 hours of sunshine, average for winter, with generally cloudy conditions during June and sunny during August. There was one thunderstorm at Sydney Airport on the 23rd of August, the first storm since April, with three storms anywhere in Sydney. Three fogs were reported at the airport, normal for winter, with a particularly heavy event on July 25th.
|Extremes in winter 2012|
30.0 °C at Sydney Airport AMO on 23 Aug|
|Warmest days on average||
18.5 °C at Richmond RAAF|
|Coolest days on average||
16.5 °C at Springwood (Valley Heights)|
16.5 °C at Terrey Hills AWS
10.7 °C at Springwood (Valley Heights) on 26 Jun|
-2.8 °C at Camden Airport AWS on 8 Aug|
|Coolest nights on average||
3.5 °C at Camden Airport AWS|
|Warmest nights on average||
9.3 °C at Sydney (Observatory Hill)|
16.1 °C at Sydney (Observatory Hill) on 23 Aug|
|Warmest on average overall||
13.9 °C at Sydney (Observatory Hill)|
|Coolest on average overall||
10.7 °C at Camden Airport AWS|
381.8 mm at Randwick Bowling Club|
102.4 mm at Potts Hill Reservoir on 12 Jun|
|Highest wind gust||
117 km/h at Port Botany (Molineux Point AWS) on 5 Jun|
|Summary statistics for winter 2012|
|Badgerys Creek AWS||17.8||28.8||23 Aug||4.5||-1.1||8 Aug||107.2|
|Bankstown Airport AWS||18.3||+0.4||29.5||23 Aug||5.8||-0.2||0.6||4 Aug||163.6||168.7||average||97%|
|Camden Airport AWS||17.8||-0.2||29.3||23 Aug||3.5||-0.3||-2.8||8 Aug||110.4||142.9||average||77%|
|Campbelltown (Mount Annan)||17.9||28.9||23 Aug||4.1||-1.2||8 Aug||101.2|
|Canterbury Racecourse AWS||17.9||29.0||23 Aug||6.2||0.4||8 Aug||226.2|
|Holsworthy Control Range||17.8||28.9||23 Aug||4.9||-0.7||5 Aug||123.0|
|Horsley Park Equestrian Centre AWS||17.6||28.4||23 Aug||6.0||0.1||7 Aug||133.4|
|Liverpool (Michael Wenden Centre)||18.3||28.9||23 Aug||5.0||0.1||3 Jul||110.2|
|Parramatta North (Masons Drive)||17.9||-0.1||29.1||23 Aug||6.7||-0.2||2.3||2 Aug||208.8||188.2||average||111%|
|Penrith Lakes AWS||18.2||28.9||23 Aug||6.0||0.7||8 Aug||89.6|
|Prospect Reservoir||28.7||23 Aug||6.7||-0.1||1.7||8 Aug||146.7||182.0||average||81%|
|Richmond RAAF||18.5||29.4||23 Aug||4.1||-2.4||8 Aug||93.0|
|Riverview Observatory||18.0||+0.6||28.7||23 Aug||3.0||8 Aug||290.1||271.5||average||107%|
|Springwood (Valley Heights)||16.5||26.5||23 Aug||6.9||2.2||7 Aug||112.6||187.7||average||60%|
|Sydney (Observatory Hill)||18.4||+1.4||29.2||23 Aug||9.3||+0.5||5.6||8 Aug||319.4||310.7||average||103%|
|Sydney Airport AMO||18.3||+0.7||30.0||23 Aug||9.1||+1.2||5.4||20 Jul||264.2||267.3||average||99%|
|Terrey Hills AWS||16.5||27.9||23 Aug||8.1||3.4||24 Jun||237.8|
A Seasonal Climate Summary is prepared to list the main features of the weather in Sydney - Greater Sydney using the most timely and accurate information available on the date of publication; it will generally not be updated. Later information, including data that has had greater opportunity for quality control, will be presented in the Monthly Weather Review, usually published in the fourth week of the month.
This statement has been prepared based on information available at 8 am on Monday 3 September 2012. Some checks have been made on the data, but it is possible that results will change as new information becomes available.
Averages are long-term means based on observations from
all available years of record, which vary widely from site to site.
They are not shown for sites with less than 20 years of record, as they cannot then be calculated reliably.
The median is sometimes more representative than the mean of long-term average rain.
The Rank indicates how rainfall this time compares with the climate record for the site,
based on the
(very low rainfall is in decile 1, low in decile 2 or 3,
average in decile 4 to 7, high in decile 8 or 9
and very high is in decile 10).
The Fraction of average shows how much rain has fallen this time as a percentage of the long-term mean.