Thursday, 1 September 2011 - Seasonal Climate Summary for Sydney - Greater Sydney - Product code IDCKGC15L0
Sydney Observatory Hill recorded 428.2 mm during winter 2011, well above the historical average of 309.8 mm and the wettest winter since 2007. The high winter totals were predominantly due to a strong East Coast Low during July, which was the wettest for Sydney since 1950, with below average rainfall recorded in both June and August. Rainfall was generally above average throughout coastal Sydney, but closer to average at western stations where the ECL impact was limited.
Sydney Observatory hill recorded 40 rain days during winter of which ten exceeded 10 mm, close to the historical averages for winter. Only four days had rainfall above 25 mm, all associated with the ECL event 20-23 July, which was the wettest four-day period in winter since an ECL in August 1998.
The average maximum temperature at Observatory Hill during winter was 18.4 °C, 1.4 °C above the historical average of 17.0 °C. This is the 22nd consecutive winter with above average maximum temperatures at Observatory Hill. Temperatures were above average throughout winter, with particularly warm conditions during the first week of August, including the longest spell of days above 20 °C on record for midwinter between July 28 and August 6. Throughout the Metropolitan region, temperatures were generally within 1 °C of average, warmer in the eastern suburbs and closer to average in the west.
Observatory Hill recorded average minimum temperatures of 9.8 °C during winter, 1.1 °C above the historical average, with above average minimums recorded throughout the Metropolitan region. The mean temperature during winter was consequently 14.1 °C, 1.2 °C above average and the 8th warmest winter on record. Winter mean temperatures at Observatory Hill have not been below the all time average of 12.9 °C since 1978.
Winds were predominantly westerly to northwesterly during winter, forming 68% of 9am winds and 39% of 3pm winds. There were 15 strong wind days during the season, close to the winter average of 13 days. Most of these occurred during July, which was the windiest since 1999, with strong winds causing significant damage in the Blue Mountains on the 7th and 8th.
Sydney Airport recorded an average of 6.5 hours of sunshine during winter, slightly below the historical average of 6.8 hours. Sunshine was lowest during August, with close to average sunshine during June and July. There was only one thunderstorm at Sydney Airport during winter, below the winter average of 4 storms, with five storms reported anywhere in the Metropolitan area.
|Extremes in winter 2011|
|Hottest day||27.2 °C at Sydney Olympic Park (Sydney Olympic Pk A on 4 Aug|
|Warmest days on average||
18.4 °C at Penrith Lakes AWS|
18.4 °C at Sydney (Observatory Hill)
18.4 °C at Sydney Olympic Park (Sydney Olympic Pk A
|Coolest days on average||
16.5 °C at Springwood (Valley Heights)|
16.5 °C at Terrey Hills AWS
|Coldest day||9.5 °C at Richmond RAAF on 13 Jul|
|Coldest night||-3.1 °C at Richmond RAAF on 9 Jul|
|Coolest nights on average||4.5 °C at Camden Airport AWS|
|Warmest nights on average||9.8 °C at Sydney (Observatory Hill)|
|Warmest night||16.1 °C at Sydney (Observatory Hill) on 1 Jun|
|Warmest on average overall||14.1 °C at Sydney (Observatory Hill)|
|Coolest on average overall||11.2 °C at Camden Airport AWS|
|Wettest overall||494.7 mm at Castle Cove (Rosebridge Ave)|
|Wettest day||132.6 mm at Duffys Forest (Namba Rd) on 22 Jul|
|Highest wind gust||104 km/hr at Wattamolla AWS on 19 Aug|
|Summary statistics for winter 2011|
|Badgerys Creek AWS||17.9||25.3||4 Aug||5.1||-1.7||12 Jul||155.8|
|Bankstown Airport AWS||17.9||0.0||25.9||4 Aug||6.5||+0.6||0.6||8 Jul||198.0||168.9||average||117%|
|Camden Airport AWS||17.9||-0.1||25.1||4 Aug||4.5||+0.7||-2.1||8 Jul||148.0||143.8||average||103%|
|Campbelltown (Mount Annan)||18.0||25.6||4 Aug||5.0||-2.0||8 Jul||169.8|
|Canterbury Racecourse AWS||17.9||25.6||3 Aug||6.8||0.9||8 Jul||290.0|
|Holsworthy Control Range||17.7||25.5||4 Aug||5.7||-1.8||8 Jul||205.8|
|Horsley Park Equestrian Centre AWS||17.6||25.1||4 Aug||6.4||0.1||8 Jul||158.4|
|Parramatta North (Masons Drive)||18.0||-0.1||25.8||4 Aug||7.2||+0.3||1.0||9 Jul||256.3||187.8||high||136%|
|Penrith Lakes AWS||18.4||25.9||4 Aug||6.4||-0.3||9 Jul||101.4|
|Prospect Reservoir||17.3||-0.3||25.2||4 Aug||6.9||+0.1||0.8||8 Jul||168.5||182.3||average||92%|
|Richmond RAAF||18.1||26.1||4 Aug||4.9||-3.1||9 Jul||109.6|
|Riverview Observatory||17.9||+0.5||26.1||3 Aug||8.2||+1.1||2.9||8 Jul||400.8||271.3||high||148%|
|Springwood (Valley Heights)||16.5||25.5||3 Aug||7.3||0.9||9 Jul||122.6||188.3||average||65%|
|Sydney (Observatory Hill)||18.4||+1.4||25.7||3 Aug||9.8||+1.1||5.5||8 Jul||428.2||310.6||high||138%|
|Sydney Airport AMO||18.2||+0.6||25.9||3 Aug||9.7||+1.8||5.4||15 Jul||341.0||267.4||high||128%|
|Sydney Olympic Park (Sydney Olympic Pk A||18.4||27.2||4 Aug||8.7||4.1||8 Jul||280.4|
|Terrey Hills AWS||16.5||24.0||4 Aug||8.1||1.9||9 Jul||325.4|
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 10 am on Thursday 1 September 2011. 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.