Sydney in December 2010: Warm start to summer

  • Above average maximum temperatures.
  • 14th consecutive year with abover average minimum temperatures.
  • Above average rainfall.

Rainfall

Sydney recorded 83.2 mm during December, which is slightly above the historical average of 77.8 mm (all years of record). This was the wettest December since 123.2mm were recorded in 2007, the only other December this decade with above average rainfall. The rain fell on ten days, which is close to the historical average of eleven days. Rainfall was heighest in the Blue Mountains, with totals exceeding 150mm at Valley Heights and Springwood, while Campbelltown experienced its wettest December since 1971.

The majority of the rain fell as a result of moist onshore flow at the beginning of the month, with a total of 48.6mm occurring over the 1st and the 2nd, reaching 50mm at Valley Heights on the 1st. Smaller falls were recorded on the 17th (7.6 mm), associated with the passage of a low pressure trough, the 20th (4.8 mm) associated with a low pressure system near Tasmania, and on the 27th (17mm) as a result of a low pressure trough.

Sydney's water storage is currently at 72.5% of capacity. This is an increase of 10% from November levels (61.3%), and 20% higher than at the end of 2009 (52.6%). Current water storage information can be found on the new Bureau of Meteorology Water Storage web site.

Temperature

The average maximum temperature at Sydney Observatory Hill was 25.8°C which is above the historical December average of 25.2°C (all years of record). This is slightly warmer than December 2009 (25.4°C) but cooler than the average of 25.9°C in December 2008. Temperatures were close to average throughout the month at Observatory Hill, with three days exceeding 30°C (equal to the average) and a max of 31.3°C but only one day below 20°C (19.9°C on the 27th). The warmest day of the month was New Years Eve, with temperatures up to 35.9°C in western regions. However, western regions were cooler on average than the coastal areas, with below average maximums at Parramatta, Bankstown and Camden during the month.

Minimum temperatures averaged 18.9°C during December, which is well above the historical average of 17.5°C but cooler than December 2009 (19.0°C). The last time Observatory Hill had below average minimums in December was in 1996 (17.1°C). Twenty-two warm nights (minimum temperature >= 18°C) were recorded, which is well above the December average of 14 nights. In particular, nine consecutive warm nights occurred between the 2nd and 10th of the month, with the warmest December minimum since 2005 on the 10th (22.8°C). Later in the month, a cold snap saw the night-time temperature at Sydney Observatory Hill plummet to 13.3°C (20th), which was the coldest night-time temperature for Sydney in December since 2004.

Wind

Coastal Sydney experienced prevailing northeasterly to southeasterly winds during December, with a frequency of 87% from this direction at 3pm, which is slightly above average for this time of year. The highest wind gust at Sydney Airport was 80 km/hr from the south on the 26th, associated with a low pressure trough, with a maximum wind gust anywhere in Sydney of 81km/hr at Kurnell on the 20th.

Other phenomena

No thunderstorms were reported at Sydney Airport during December (historical average 3.6 storms), with only three storms in the entire Sydney metropolitan region. Sunshine at Sydney Airport averaged 8.2 hours per day during the month, above the historical average of 7.9 hours per day, although 3pm cloudiness was slightly above the historical average of 4.5 oktas (4.7 during December 2010).

Further information

Media
(03) 9669 4057
Enquiries

Extremes in December 2010
Hottest day 35.9 °C at Penrith Lakes AWS on the 31st
Warmest days on average 28.3 °C at Prospect Reservoir
Coolest days on average 25.1 °C at Terrey Hills AWS
Coldest day 17.5 °C at Springwood (Valley Heights) on the 27th
Coldest night 8.8 °C at Camden Airport AWS on the 21st
8.8 °C at Campbelltown (Mount Annan) on the 21st
Coolest nights on average 15.3 °C at Campbelltown (Mount Annan)
Warmest nights on average 18.9 °C at Sydney (Observatory Hill)
Warmest night 23.9 °C at Sydney Olympic Park (Sydney Olympic Pk A on the 9th
Warmest on average overall 22.9 °C at Sydney Olympic Park (Sydney Olympic Pk A
Coolest on average overall 20.9 °C at Springwood (Valley Heights)
Wettest overall 161.8 mm at Valley Heights (Sun Valley Rd)
153.6 mm at Springwood (Valley Heights)
Wettest day 50.0 mm at Valley Heights (Sun Valley Rd) on the 1st
Highest wind gust 81 km/h at Kurnell AWS on the 20th

Summary statistics for December 2010
Maximum temperatures
for December
(°C)
Minimum temperatures
for December
(°C)
Rainfall
for December
(millimetres)
Mean for
December
2010
Diff
from
average
Highest for
December
2010
Mean for
December
2010
Diff
from
average
Lowest for
December
2010
Total for
December
2010
Average
for
December
Rank of
December
2010
Fraction of
December
average
Badgerys Creek AWS 27.1   34.1 31st 15.9   10.6 22nd 131.2
Bankstown Airport AWS 27.2 -0.1 32.4 9th 17.2 +0.6 12.4 20th 77.0 67.2 average 115%
Camden Airport AWS 27.5 -1.0 34.6 31st 15.6 +0.5 8.8 21st
Campbelltown (Mount Annan) 27.2   34.1 31st 15.3   8.8 21st
Canterbury Racecourse AWS 26.4   31.7 9th 17.2   11.1 21st 64.8
Holsworthy Control Range 26.9   31.9 31st 15.9   9.2 21st 96.2
Horsley Park Equestrian Centre AWS 27.3   33.9 31st 16.2   9.8 20th 79.2
Liverpool (Michael Wenden Centre) 27.3   31.9 23rd 16.2   11.6 21st 81.0
Parramatta North (Masons Drive) 27.1 -0.4 32.2 31st 16.6 +0.4 11.6 21st 90.0 70.2 high 128%
Prospect Reservoir 28.3 +0.9 33.3 31st 17.0 +0.7 12.0 20th 97.0 75.2 high 129%
Richmond RAAF 27.8   35.1 31st 16.7   11.2 21st 55.2
Riverview Observatory 26.2 +0.4 31.1 9th 17.4 +1.1 11.8 20th 79.1 83.0 average 95%
Springwood (Valley Heights) 26.1   33.1 31st 15.8   10.0 20th 153.6 102.1 high 150%
Sydney (Observatory Hill) 25.8 +0.6 31.3 26th 18.9 +1.4 13.3 20th 83.2 77.9 average 107%
Sydney Airport AMO 26.7 +1.0 32.8 9th 18.8 +1.3 13.3 20th 105.6 73.8 high 143%
Sydney Olympic Park (Sydney Olympic Pk A 27.4   32.9 23rd 18.4   13.1 20th 86.4
Terrey Hills AWS 25.1   30.2 9th 17.0   10.6 20th 90.8

Daily rainfall
Hunter (61)12345678910111213141516171819202122232425262728293031
Webbs Ck-Wisemans Ferry (Hawkesbury Rive 11.0 10.8 12.0 1.0 2.0 - - - - 2.5 - - - - - - 33.0 - - 5.8 0.2 - - - - - 1.0 1.0 - - -
Central Tablelands (South) (63)12345678910111213141516171819202122232425262728293031
Sackville Ferry (Hawkesbury River) 38.6 10.8 2.4 9.4 4.0 0.2 - - 0.2 0.2 - - - - - - 10.0 - - 3.6 - - - - - 5.4 5.4 1.4 - - -
Springwood (Valley Heights) 49.6 14.0 1.0 10.6 4.6 - 1.0 - 1.2 2.8 - - - - - - 29.8 - - 3.6 - - - - - 6.2 23.2 6.0 - - -
Valley Heights (Sun Valley Rd) 50.0 12.0 2.8 9.0 7.0
1.0 - 1.0 5.2
- - -

44.8
- 4.0 - -
- - 6.0 14.0 5.0
- -
Metropolitan (East) (66)12345678910111213141516171819202122232425262728293031
Abbotsford (Blackwall Point Rd) 25.0 19.5

2.0










7.0

8.0










Auburn (Rosnay Golf Club) 22.0 16.0 - 1.0 2.0 - 19.0 - - 1.0 - - - - - - 13.0 - - 6.0 - - - - - 2.0 21.0 2.0 - - -
Audley (Royal National Park) 31.0 32.0 - - - 7.0 - - 1.0 2.0 - - - - - - 4.0 - - 5.0 - - - - - 1.0 15.0 1.0 - - -
Avalon (Wollstonecraft Ave) 38.0 29.0 - 1.0 3.0 - - - - - - - - - - - 23.0 - - 4.0 - - - - - - - 1.0 - - -
Avalon Beach (Avalon (Palmgrove Rd)) 35.8 25.6






0.8



















-
Bankstown Airport AWS 16.6 15.8 1.4 0.2 0.4 - 3.0 - 0.6 1.4 0.4 - - - - - 14.4 - - 5.0 - - - - - 2.2 14.4 1.2 - - -
Belrose (Evelyn Place) 40.8 22.8
0.4 4.0 8.8


0.4 0.4




7.8

7.0




1.6 7.8 2.6

-
Campbelltown (Ingleburn (Long Point)) 29.0 20.0 2.0 - - 1.0 23.0 - 2.0 3.0 - - - - - - 3.0 - - 8.0 - - - - - 3.0 37.0 1.0 - - -
Canterbury Racecourse AWS 22.2 18.4 - - 0.2 0.2 - - - 0.2 0.8 - - - - - 6.4 - -
- - - - - 0.8 13.0 2.6 - - -
Castle Cove (Rosebridge Ave) 31.0 25.0

3.0 2.0









6.0

7.0




1.0 28.0



Chatswood Bowling Club 25.0 16.0 - 1.0 - 1.0 - - - - - - - - - - 3.0 - - 5.0 - - - - - 2.0 25.0 2.0 - - -
Collaroy (Long Reef Golf Club) 33.6 29.2

4.8



0.2





3.4













Concord Golf Club 22.4 17.2
0.4 1.4 0.4


















1.2 21.6 2.4


Cronulla South Bowling Club 39.0 33.0




























Guildford (Woodville Golf Club) 23.0 15.0 2.0 1.0 1.0 1.0 4.0 - - 1.0 - - - - - - 16.0 - - 7.0 - - - - - 2.0 21.0 1.0 - - -
Holsworthy Control Range 20.8 14.6 2.2 - - 1.0 17.0 - 1.2 1.8 0.6 - - - - - 2.2 - - 4.4 - - - - - 2.8 26.2 1.0 0.4 - -
Lidcombe (Carnarvon Golf Club) 19.0 20.0 - - 2.0 - 2.0 - - 1.0 2.0 - - - - - 9.0 - - 4.0 - - - - - - 13.0 1.0 - - -
Liverpool-Scrivener St (Georges River) 20.0 13.0 4.0 - - - - - 1.0 - - - - - - - 18.0 - - 6.0 - - - - - 3.0 15.0 - - - -
Lucas Heights (ANSTO) 23.0 27.2 0.8

3.2

2.0 1.6





4.0

4.2




2.7 28.0 2.2


Manley / Warringah (Allambie) 33.0 21.5 - - 3.0 - 0.5 - - - - - - - - - 4.5 - - 5.0 - - - - - 0.5 5.5 1.5 - - -
Manley / Warringah (Belrose) 30.5 21.0 - - 3.5 11.0 - - - - 0.5 -
- - - 6.5 - - 5.0
- -
- -
2.5 - - -
Marrickville Golf Club 24.0 16.0 - - - 5.0 - - - 1.0 - - - - - - 5.0 - - 6.0 - - - - - 1.0 15.0 2.0 - - -
Milperra Bridge (Georges River) 17.0 16.0 1.0 - - - 1.0 - - - 1.0 - - - - - 22.0 - - 3.0 - - - - - 1.0 10.0 1.0 - - -
Mona Vale Golf Club 44.8 34.2 - 0.2 5.8 - - - - 1.8 - - - - - - 24.8 - - 4.2 - - - - - 1.0 3.4 0.6 - - 0.2
Newport Bowling Club 37.4 31.4 - - - 6.4 - - - - 2.0 - - - - - 23.0 - - 6.0 - - - - - - 4.2 - - - -
Parramatta (Erts) 20.5 14.5 1.5 0.5 11.0 - - - - 0.5 - - - - - - 13.0 - - 5.5 - - - - - 1.0 9.0 1.5 - - -
Parramatta North (Masons Drive) 27.4 15.8 2.0 0.6 2.0 - 0.4 - - 0.4 - - - - - - 19.6 - 0.2 5.0 - - - - - 3.0 11.8 1.8 - - -
Peakhurst Golf Club 26.0 20.0 - - - - 1.0 - - 2.0 - - - - - - 13.0 - - 7.0 - - - - - 2.0 23.0 - - - -
Potts Hill Reservoir 18.0 20.0 - »» »» 1.6 0.6 - 1.8 - »» »» 0.2 - - - 13.0 »» »» 5.0 - - - - - - - - - - -
Riverview Observatory 23.2 16.6 - 0.2 1.0 »» 0.4 - - - - - - - - - 7.4 - - 6.4 0.1 - - - - 2.2 18.0 3.6 - - -
Rose Bay (Royal Sydney Golf Club) 39.4 48.6 - - 1.8 2.8 - - - - - - - - - - 4.2 - - 7.4 - - - - - 1.0 14.4 2.2 - - -
Sans Souci (Public School) 32.0 34.0 - - - - - - - 1.0 1.0 - - - - - 6.0 - - 6.0 - - - - - - 19.0 2.0 - - -
St Ives (Richmond Avenue) 30.2 17.0 0.2 2.0 3.6 8.2 0.2

0.6





17.2
0.2 8.2




1.6 7.2 3.8

-
Strathfield Golf Club 22.0 20.0 - - 1.0 - - - - 1.0 - - - - - - 11.0 - 1.0 6.0 - - - - - 2.0 14.0 3.0 - - -
Sydney (Observatory Hill) 27.6 21.0 0.2 - 1.4 1.0 - - - - - - - - - - 7.6 - - 4.8 - - - - - 0.8 17.0 1.8 - - -
Sydney Airport AMO 26.4 29.6 - - 0.2 4.0 0.8 - - 0.6 0.4 - - - - - 4.8 - - 4.8 - - - - - 0.4 31.0 2.6 - - -
Sydney Olympic Park (Sydney Olympic Pk A 23.2 21.0 - 0.8 2.2 - 0.4 - - 0.2 0.8 - - - - - 8.8 - - 7.8 - - - - - 1.8 17.8 1.6 - - -
Terrey Hills AWS 34.6 22.2 - 1.0 5.2 - - - - 0.4 - - - - - - 10.2 - - 7.8 - - - - - 1.6 5.2 2.6 - - -
Turramurra (Kissing Point Road) 38.2 21.6
1.6 3.6
3.4

1.0 0.6



1.4 13.2
0.4 8.2




1.6 18.6 2.4

-
Metropolitan (West) (67)12345678910111213141516171819202122232425262728293031
Abbotsbury (Fairfield City Farm) 25.0 11.0 1.0 - - - 5.0 - 1.0 1.0 - - - - - - 15.0 - - 4.0 - - - - - 3.0 11.0 1.0 - - -
Badgerys Creek AWS 28.8 14.0 0.8 1.2 0.4 0.8 28.4 - 2.0 2.6 - - - - - - 22.0 - 0.4 2.4 - -
- - 4.8 21.0 1.4 0.2 - -
Baulkham Hills (Swimming Pool ) 19.5 11.0 12.0 1.0 1.5 1.5 - - - - - - - - - - - 0.5 - 6.0 - - - - - 1.5 15.5 1.0 - - -
Baulkham Hills Eucalyptus Ct 22.0 12.0 15.5 1.0 2.0 - - - - - - - - - - - 35.5 - - 5.5 - - - - - 2.0 11.5 0.5 - - -
Berowra (Goodwyn Road) 36.0 22.4
6.2 6.2










19.0

4.0




1.2 3.4


-
Blacktown (Dog Pound) 17.5 12.0 2.0 0.5 3.0 2.5 0.5 - - 1.0 - - - - - - 21.5 - - 5.0 - - - - - 2.5 16.5 1.0 - - -
Box Hill (Hynds Road) 19.0 9.0 - 3.0 3.0 1.0 - - - - - - - - - - 43.0 - - 2.0 - - - - - 3.0 5.0 - - - -
Castle Hill (Kathleen Ave) 20.2 11.0 10.6 0.6 3.0 6.4 0.2

0.3





23.4
0.5 6.2




2.2 15.4 1.5


Glenorie (Old Northern Rd) 22.0 11.4 6.6
2.0 6.0









21.0

7.6




4.0 8.0



Greystanes (Cumberland Golf Club) 24.5 12.5 7.0 0.5 0.5 - - - - 0.5 0.5 - - - - - 18.5 0.5 - 6.0 - - - - - 2.0 17.5 3.0 - - -
Hawkesbury River (Sackville Downstream) 10.5 8.5 2.0 1.0 3.5 0.5 - - - 0.5 - - - -
- 10.0 - - 3.5 - - - - - - 5.0 2.0 - - -
Horsley Park Equestrian Centre AWS 25.4 10.4 0.4 0.2 0.6 - 0.2 - 0.4 1.6 0.2 - - - - - 20.2 - - 4.0 - - - - - 4.0 9.0 2.6 - - -
Kelso Ck (Kelso Creek U/S Levee (Georges 16.5 15.5 - 0.5 - - - - 0.5 2.0 - - - - - - 12.0 - - 6.0 - - - - - 2.0 23.0 1.0 - - -
Kings Langley (NSW Soccer Federation) 17.5 10.5 6.0 0.5 3.0 0.5 - - - - - - - - - - 25.0 - - 6.0 - - - - - 2.0 9.5 - 0.5 - -
Kings Langley (Solander Rd) 18.8 11.0 10.0 0.8 4.0 - - - - 0.4 - - - - - - 32.4 - 0.2 4.6 - - - - - 2.2 8.6 1.2 - - -
Liverpool (Michael Wenden Centre) 28.2 13.6 4.4 - 0.2 - - - 1.2 2.2 0.4 - - - - - »» 10.4 - 5.4 - - - - »» »» 13.4 1.6 - - -
Lower Portland (Hawkesbury River) 48.4 12.0 10.2 11.8 3.6 0.4 - - - 0.6 0.4 - - - - - 1.2 - - 3.2 - - - - - 5.8 4.6 1.4 0.2 - -
Maroota (Tobruk) 30.0 12.2 3.0 16.4 2.4 - - - - 2.0 0.2 - - - - - 22.4 - - 3.6 - - - - - 6.8 3.0 0.8 - - -
Merrylands (Welsford Street) 39.2 14.8 12.6

4.4









14.8

6.4




6.4 9.8



Merrylands West (Finlayson Creek) 32.5 16.5 20.5 0.5 0.5 1.0 - - - 1.0 1.0 - - - - - 19.5 - - 7.5 - - - - - 3.0 22.5 3.0 - - -
North Parramatta (Burnside Homes) 23.5 14.5 1.5 0.5 1.5 - - - - - - 0.5 - - - - 18.5 - - 4.5 - - - - - 1.5 12.5 1.5 - - -
North Rocks (Muirfield Golf Club) 23.5 14.0 3.0 0.5 2.0 - - - - - - - - - - - 22.0 - - 5.5 - - - - - 2.0 14.5 1.0 - - -
Northmead Bowling Club 20.0 10.5 6.0 0.5 2.0 - - - - - - - - - - - 20.0 - - 4.5 - - - - - 1.5 9.5 1.5 - - -
Parramatta (Baulkham Hills West (Sierra 20.0 10.5 11.0 0.5 3.5 - - - - - - - - - - - 30.0 - - 4.5 - - - - - 1.5 9.5 1.0 - - -
Penrith Lakes AWS 25.2 4.2 0.4 4.6 1.8 1.0 0.2 - 0.6 1.8 - - - - - -



- - - -




- -
Prospect Reservoir 29.2 13.3 4.4 0.8 0.8 - - - 0.2 1.2 0.1 - - - - - 22.2 0.1 - 3.4 - - - - - 1.7 18.4 »» 1.2 - -
Richmond RAAF 26.8 5.4 0.2 6.2 4.6 1.4 0.2 - - - 0.4 - - - - -
- -
- 0.8 - - - 3.0 4.6 0.4 0.2 - -
Seven Hills (Radio FM 103.2) 20.5 12.5 1.5 1.0 4.5 - 0.5 - - 0.5 - - - - - - 34.5 - - 6.0 - - - - - 2.0 9.0 0.5 - - -
Seven Hills (Collins St) 19.8 14.0 3.8
7.4










33.4

7.2




3.2 8.2



St Clair (Juba Close) 15.0 6.0 2.0 2.0 1.0 1.0 11.0 - - 2.0 - 1.0 - - - - 28.0 - - 4.0 - - - - - 5.0 8.0 1.0 - - -
Toongabbie Bowling Club 20.5 9.5 14.0 - 3.5 - - - - 0.5 - - - - - - 39.0 - - 6.5 - - - - - 2.0 11.0 1.0 - - -
Toongabbie Ck (Redbank Road (Toongabbee 21.5 12.0 7.0 0.5 1.5 - - - - - 0.5 - - - - - 17.5 - - 9.0 - - - - - 2.0 12.5 0.5 - - -
West Pennant Hills (Cumberland S F Alert 20.0 13.0 2.0 1.0 2.0 - 0.5 - - - 0.5 - - - - - 12.0 - 0.5 6.0 - - - - - 1.5 10.0 2.5 - - -
Willmot (Resolution Ave) 10.0 5.0 1.0 1.0 8.0 - - - - - - - - - - - 22.0 - - - - - - - - 4.0 3.0 1.0 - - -
Windsor SWC (Hawkesbury River) 29.0 6.0 - 5.0 2.0 4.0 2.0 - - - - - - - - - 31.0 - - 2.0 - - - - - 1.0 2.0 - - - -
Illawarra (68)12345678910111213141516171819202122232425262728293031
Camden Airport AWS




















- - - - 6.6 10.8 0.2 - - -
Camden Valley Golf Resort 27.0 15.0 - 1.0 1.0 11.0 1.0 - 3.0 3.0 - - - - - - 6.0 - - 2.0 - - - - - 5.0 23.0 1.0 - - -
Campbelltown (Kentlyn (Georges River Roa 20.0 22.0 1.0 - - - 7.0 - 2.0 3.0 1.0 - - - - - 10.0 - - 5.0 - - - - - 4.0 30.0 - - - -
Campbelltown (Mount Annan)

0.6 0.2 2.2 9.2 0.4 0.2 2.6 4.0 - - - - - - 4.0 0.2 0.2 1.4 - 0.2 - - - 5.4 18.2 0.8 - - -
Rossmore (South Creek) 26.0 9.0 1.0 - - - 3.0 - 3.0 2.0 - - - - - - 22.0 - 1.0 3.0 - - - - - 4.0 28.0 2.0 - - -

Most values are the precipitation in the 24 hours to 9 am on the day indicated. Days marked with »» are part of a longer accumulation, which is marked like this on the final day. Values over 100 mm have been rounded to the nearest whole millimetre. Days marked with - have a rainfall report of zero; days left blank have no rainfall report (which often indicates no rain fell).
This table is very wide; you may have to scroll sideways to see all the days, and you may need to set the paper to 'landscape' to print.


Notes

A Monthly 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 12 pm on Tuesday 4 January 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