Sydney in winter 2011: Warm, wet winter in Sydney

  • Above average rainfall, wettest winter since 2007
  • 22nd consecutive winter with above average maximum temperatures at Observatory Hill
  • 8th warmest winter mean temperatures on record
  • 10 consecutive days above 20 °C, equal warmest spell for winter and warmest this close to midwinter.

Rainfall

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.

Temperature

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.

Wind

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.

Other phenomena

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.

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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 gust104 km/hr at Wattamolla AWS on 19 Aug

Summary statistics for winter 2011
Maximum temperatures
for winter
(°C)
Minimum temperatures
for winter
(°C)
Rainfall
for winter
(millimetres)
Mean for
winter
2011
Diff
from
average
Highest for
winter
2011
Mean for
winter
2011
Diff
from
average
Lowest for
winter
2011
Total for
winter
2011
Average
for
winter
Rank of
winter
2011
Fraction of
winter
average
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

Notes

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 decile ranking (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.

Further information

Media
(03) 9669 4057
Enquiries