Cool, wet end to warm December in Sydney

  • Slightly above average maximum temperatures
  • Well above average minimum temperatures, 8th highest on record
  • Very hot day on 17th with record high temperatures in some locations
  • Close to average rainfall
  • Average sunshine

Rainfall

Following a dry November, Sydney recorded close to average rainfall during December. Observatory Hill had a total rainfall of 66.8 mm, which is close to the historical average of 77.8 mm or 86% of the normal monthly rainfall. Most of the rain was recorded during a cool, wet spell in the last week of the month. The rain fell on 9 days, which is slightly below the average of 11 rain days. Most of the metropolitan area recorded close to average rainfall with the far southwest recording slightly above average rainfall. Monthly totals in metropolitan Sydney ranged from 95.5 mm at North Rocks in the northwest to 47 mm at Peakhurst in the southwest. Heavy rain on the 28th produced 39.5 mm at North Rocks, the highest daily rainfall in the metropolitan area during December.

Slow moving high pressure systems and weak cold fronts brought mostly dry conditions to Sydney for much of the month. However, during the last week, an inflow of moist tropical air from ex-TC Laurence and a slow moving low pressure trough caused cool, showery weather over the metropolitan area.

Dry conditions also prevailed over the Warragamba Dam catchment until a rainy spell during the last week. Most totals were 80 to 100 mm for the month. The below average rainfall caused Sydney's storage levels to fall by 2% during December and is currently around 53% of capacity. Recent rainfall and current levels in Sydney's water catchments can be found on the Sydney Catchment Authority web site http://www.sca.nsw.gov.au/dams/rainfall.html

Temperatures

Warm, dry days prevailed in Sydney during December until the last week of the month which was cool and cloudy. The average maximum temperature at Observatory Hill was 25.5 °C, which is 0.3 °C above the historical December average. It was up to 5 °C hotter in Sydney's western suburbs with an average maximum of 30.7 °C at Penrith.

Sydney Observatory Hill recorded only 1 hot day (temperature over 30 °C) on 17 December, when the maximum reached 32.0 °C. This compares with an historic average of 3 hot days. On the same day, the maximum at Camden Airport of 43.1 °C was the highest ever recorded in December at this site.

Some sites had their highest December temperature on record.

Warm nights were also experienced throughout the metropolitan area during December. The average minimum at Observatory Hill of 19.0 °C was 1.5 °C above the historic average and the 8th highest on record. Warm nights were common during December with 22 nights recording a minimum greater than 18 °C. The normal frequency for December is 14 nights above 18 °C. Although minimums were generally a little cooler in the western suburbs, monthly averages were around 1 °C above the historical average.

There was significant variation in temperatures over the Sydney region during December, with extremes ranging from a high of 43.1 °C at Camden Airport on the 17th to a low of 9.7 °C at Campbelltown on the 3rd. The warmest night was 22.2 °C at Sydney Airport on the 17th.

Wind

Coastal Sydney experienced prevailing NE winds during December, with a frequency of 45% from this direction at 3pm compared to the historic average of 32% from this direction. The highest wind gust was 80 km/h at Sydney Airport on the 24th due to a very strong NE sea-breeze.

Other phenomena

Observatory Hill recorded only 1 thunderstorm during the month, on the 17th, while 2 storms were recorded at Sydney Airport. The historical average is 4 storms for December. Sunshine averaged 7.9 hours per day, which is average for December.

Further information

Media
(03) 9669 4057
Enquiries

Extremes in December 2009
Hottest day 43.1 °C at Camden Airport AWS on the 17th
Warmest days on average 30.7 °C at Penrith Lakes AWS
Coolest days on average 25.3 °C at Terrey Hills AWS
Coldest day 18.4 °C at Springwood on the 26th
Coldest night 9.7 °C at Campbelltown on the 3rd
Coolest nights on average 15.7 °C at Campbelltown
Warmest nights on average 19.2 °C at Sydney Airport
Warmest night 22.2 °C at Sydney Airport on the 17th
Wettest overall 95.5 mm at North Rocks
93.4 mm at Turramurra
Driest overall 47.0 mm at Peakhurst
Wettest day 39.5 mm at North Rocks on the 28th
Highest wind gust 80 km/h at Sydney Airport on the 24th

Record highest December temperature
Highest temperature
in December 2009 (°C)
Previous highest
for December
Years of
record
Average for
December
Camden Airport AWS 43.1 on the 17th 42.0 on the 22nd in 2002 34 28.5



Summary statistics for December 2009
Maximum temperatures
for December
(°C)
Minimum temperatures
for December
(°C)
Rainfall
for December
(millimetres)
Mean for
December
2009
Diff
from
average
Highest for
December
2009
Mean for
December
2009
Diff
from
average
Lowest for
December
2009
Total for
December
2009
Average
for
December
Rank of
December
2009
Fraction of
December
average
Sydney (Observatory Hill) 25.5 +0.3 32.0 17th 19.0 +1.5 13.5 2nd 66.8 77.8 average 86%
Bankstown Airport AWS 28.0 +0.7 41.2 17th 17.4 +0.8 12.3 3rd 30.0* 67.0 - -
Camden Airport AWS 29.9 +1.4 43.1 17th 15.9 +0.8 10.1 3rd 60.4 54.8 average 110%
Parramatta North 28.2 +0.7 41.8 17th 17.2 +1.0 13.0 2nd 64.2 69.8 average 92%
Penrith Lakes AWS 30.7   42.3 17th 17.8   12.6 3rd 31.4*
Prospect Reservoir 29.1 +1.7 41.7 17th 17.0 +0.7 11.1 3rd 63.2 75.0 average 84%
Richmond RAAF 30.1 +1.3 42.1 17th 17.0 +1.0 10.8 3rd 55.4 71.7 average 76%
Springwood 27.9   40.1 17th 16.0   10.9 3rd 76.6 101.7 average 75%
Terrey Hills AWS 25.3   35.2 17th 17.4   11.8 1st 78.2

* incomplete data


Daily rainfall

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.

Hunter (61)12345678910111213141516171819202122232425262728293031
Webbs Ck-Wisemans Ferry (Hawkesbury Rive 5.4 1.6 0.2 - - - - - - - - - - - - 0.2 - 3.4 13.4 0.6 0.2 - - - - 14.4 2.4 30.0 2.6 0.2 -
Central Tablelands (South) (63)12345678910111213141516171819202122232425262728293031
Sackville Ferry (Hawkesbury River) 10.6 2.4 - - - - - - - - - - - 0.2 0.4 - - 9.0 12.2 - - - - - - 9.8 2.2 24.2 0.6 - -
Springwood Bowling Club 8.0 - - - - - - - - - - - - 3.0 1.8 - - 8.8 5.4 0.4 - 1.6 0.2 - - 14.8 1.6 28.4 2.2 - 0.4
Valley Heights (Sun Valley Rd) 8.0 -

-

- 0.2 - -
- 3.2 1.8
- 9.8 6.0 0.6
2.0
- - 15.6 1.6 30.0 3.6
-
Metropolitan (East) (66)12345678910111213141516171819202122232425262728293031
Abbotsford (Blackwall Point Rd) 5.8 5.0














1.4 11.0







10.1 9.0

Auburn (Rosnay Golf Club) 3.0 3.0 - - - - - - - - - - - - - - - 7.0 5.0 - - - - - - 9.0 3.0 22.0 3.0 - -
Audley (Royal National Park) 5.0 3.0 - - - - - - 1.0 - - - - - - - - 3.0 3.0 - - - - - - 6.0 2.0 19.0 2.0 - -
Avalon (Wollstonecraft Ave) 8.0 11.0 - - - - - - - - - - - - - - - 12.0 13.0 - - - - - - 15.0 2.0 24.0 5.0 - -
Avalon Beach (Avalon (Palmgrove Rd)) 7.4 8.8 -
- - -





0.4 2.6

12.4 14.0











Bankstown Airport AWS 4.6 2.4 - - - - - - 7.4 - -
- 0.2 - - - 7.8 4.0 - - - - - -
1.8
1.8
-
Belrose (Evelyn Place) 4.2 6.4






0.4 0.2

0.4 1.2

12.0 11.0





15.6 2.8 29.6 3.4
1.0
Campbelltown (Ingleburn (Long Point)) 25.0 5.0 - - - - - - - - - - - - - - - 3.0 5.0 - - - - - - 9.0 1.0 29.0 - - -
Canterbury Racecourse AWS
3.6 - - - - - - 0.6 -

- - - - - 4.8 5.2 0.2 -
- - - 8.4
14.4 3.4 - -
Castle Cove (Rosebridge Ave) 6.0 7.5














3.5 13.5






3.0 18.0 8.0
1.0
Chatswood Bowling Club 4.0 6.0 - - - - - - - - - - - - - - - 5.0 9.0 - - - - - - 15.0 4.0 22.0 4.0 - -
Collaroy (Long Reef Golf Club) 4.0 8.6














14.0 6.6





13.2 2.0 20.6 1.8
0.6
Cronulla South Bowling Club 13.4 6.6





1.6







5.2 1.4





8.8




Guildford (Woodville Golf Club) 3.0 4.0 - - - - - - 1.0 - - - - - - - - 7.0 7.0 - - - - - - 11.0 2.0 25.0 2.0 - -
Lidcombe (Carnarvon Golf Club) 1.0 1.0 - - - - - - - - - - - - - - - 5.0 6.0 - - - - - - 8.0 2.0 15.0 2.0 - -
Liverpool-Scrivener St (Georges River) 4.0 4.0 - - - - - - 1.0 - - - - - - - - 4.0 4.0 - - - - - - 8.0 1.0 26.0 1.0 - -
Lucas Heights (ANSTO) 4.6 3.4





0.4



0.2


3.4 2.1





7.4 1.2 24.3 1.9

Manley / Warringah (Allambie) 4.5 3.5 - - - - - - - - - - - - 2.0 - - 10.0 9.0 - - - - - - 13.0 2.0 21.5 4.5 - 0.5
Manley / Warringah (Belrose) 4.0 5.5 - - -

- - -
- - - 0.5 - - 6.0 10.5 0.5 - - - - - 16.0 3.0 4.5 3.5 - 0.5
Marrickville Golf Club 6.0 6.0 - - - - - - 1.0 - - - - - - - - 6.0 4.0 - - - - - - 9.0 5.0 14.0 3.0 - -
Milperra Bridge (Georges River) 4.0 1.0 - - - - - - 5.0 - - - - - - - - 4.0 3.0 - - - - - - 7.0 1.0 18.0 1.0 1.0 -
Mona Vale Golf Club 6.2 9.6 - - - - - - - - 0.2 - - - 0.8 - - 10.0 13.0 - - - - - - 15.8 1.2 30.0 2.6 - 0.4
Parramatta (Erts) 1.2 0.8 - - - - - - - 4.6 - - - - - - - 1.4 2.2 - - - - - - 9.0 2.5 22.5 1.5 - -
Parramatta North (Masons Drive) 4.6 2.2 - - - - - - 0.6 - - - - 0.2 - - - 4.6 8.2 - - - - - - 11.6 3.4 26.4 2.0 - 0.4
Peakhurst Golf Club 3.0 2.0 - - - - - - 6.0 - - - - - - - - 5.0 4.0 - - - - - - 7.0 2.0 17.0 1.0 - -
Randwick Bowling Club 6.4






0.4



0.2 0.2

5.4 7.2





13.2 3.8
5.8
0.6
Riverview Observatory 4.2 5.0 - - - - - »» 0.8 - - - - - 0.2 - - 5.8 8.6 - - - - - - 15.0 »» 22.2


Rose Bay (Royal Sydney Golf Club) 9.8 8.2





1.2




1.8

5.2 8.6





12.4 2.4 27.4 9.6
0.6
Sans Souci (Public School) 4.0 4.0 - - - - - - 6.0 - - - - - - - - 7.0 3.0 - - - - - - 6.0 3.0 18.0 2.0 - -
St Ives (Richmond Avenue) 7.0 6.8











0.8

»» 25.2





18.8 3.0 26.6 3.0
-
Strathfield Golf Club 4.0 2.0 - - - - - - - - - - - - - - - 6.0 6.0 - - - - - - 10.0 5.0 19.0 3.0 - -
Sydney (Observatory Hill) 4.4 10.2 - - - - - - 0.6 - - - - - - - - 5.4 8.0 - - - - - - 12.0 4.8 16.0 5.4 - -
Sydney Airport AMO 5.4 10.0 - - - - - - 1.6 - - - - - - - - 5.4 4.4 - - - - - - 8.0 7.2 14.0 3.0 - -
Sydney Olympic Park 3.6 2.8 - - - - - - 0.8 - -
- - - 0.4 - 4.6 7.2 - -
- - - 11.4 5.2 22.6 3.2 - 0.2
Terrey Hills AWS 3.6 4.0 - - - - - - - 0.2 0.2
- 0.2 1.6 - - 11.0 13.0 - - - - - - 17.2 2.0 20.6 3.6 - 1.0
Turramurra (Kissing Point Road) 9.8 4.0





0.2


0.4 0.4 0.6

12.0 13.0





17.2 3.6 28.2 3.2
0.8
Metropolitan (West) (67)12345678910111213141516171819202122232425262728293031
Abbotsbury (Fairfield City Farm) 2.0 3.0 - - - - - - 2.0 - - - - - - - - 6.0 4.0 - - - - - - 9.0 2.0 30.0 1.0 - -
Badgerys Creek AWS 4.6 0.6 0.2 - - - - - 0.6 - -
- - - 0.2 - 4.2 4.2 0.2 - 0.2 0.2 - - 10.4 1.0 23.4 1.6 - -
Baulkham Hills (Swimming Pool ) 0.5 3.5 - - 0.5 - - - - - - - - - - - - 8.0 7.0 - - - - - - 9.5 2.0 23.5 1.5 - -
Baulkham Hills Eucalyptus Ct 3.0 3.5 - - 2.0 - - - - - - - - - - - - 5.0 8.0 0.5 - - - - - 10.5 1.5 29.5 2.0 - -
Berowra (Goodwyn Road) 11.2 5.2










1.2


12.6 10.6





22.6
21.6

0.8
Blacktown (Dog Pound) 2.0 5.0 - 1.0 - - - - 0.5 - - - - - - - - 6.5 4.5 - - - - - - 9.0 1.5 28.5 1.5 - -
Box Hill (Hynds Road) 2.0 5.0 - - - - - - - - - - - 1.0 - - - 7.0 6.0 1.0 - 1.0 - - - 9.0 2.0 25.0 1.0 - -
Castle Hill (Kathleen Ave) 4.6 4.0





0.6







9.9 8.4 0.1
0.2


9.9 2.2 21.2 2.8
0.4
Glenorie (Old Northern Rd) 2.1 3.4














9.4 13.0


2.4


»» 41.6

2.0
Greystanes (Cumberland Golf Club) 0.5 4.5 - - 0.5 - - - - - - - - - - - - 8.0 5.5 - - - - - - 10.0 1.5 28.0 2.0 - -
Hawkesbury River (Sackville Downstream) 10.0 2.0 - - -
- - - - - - - - 0.5 - - 3.0 10.0 0.5 - - - - - 9.0 2.0 3.0 0.5 - -
Horsley Park Equestrian Centre AWS 0.6 3.0 - - - - - - 4.4 - -
- - 0.4 - - 7.0 4.0 - - - - - - 10.2 1.6 33.4 1.2 - -
Kelso Ck (Kelso Creek U/S Levee (Georges 5.0 1.0 - - - - - - 1.0 - - - - - - - - 4.0 2.5 - - - - - - 8.5 1.5 19.5 1.0 - -
Kings Langley (NSW Soccer Federation) 0.5 6.0 - - - - - 0.5 - - - - - - - - - 5.5 6.0 - - 0.5 - - - 10.0 1.0 25.0 1.0 - -
Kings Langley (Solander Rd) 0.6 6.0 - - - - - - 0.4 - - - - - - - - 5.2 6.0 - - - - - - 10.0 1.4 27.0 1.4 - 0.2
Liverpool (Michael Wenden Centre) 8.2 4.2 - - - - - - 0.6 - - - - 0.2 - - - 5.0 5.6 - - - - - - 10.6 1.4 27.6 2.4 - -
Lower Portland (Hawkesbury River) 6.0 2.2 - - - - - - - - - - - - 0.4 - - 9.8 11.6 0.4 0.2 - -
- 12.6 1.6 22.8 2.0 0.2 -
Maroota (Tobruk) 10.4 2.0 - - - - - - 0.2 - - - - 1.0 - - - 9.4 11.8 1.0 0.6 - 0.6 - - 17.4 2.8 33.4 1.8 - 0.6
Merrylands West (Finlayson Creek) 6.0 5.0 - 1.0 - - - - 0.5 - - - - - - 0.5 - 8.5 4.5 0.5 - - - - - 9.5 1.5 23.5 2.0 - -
North Parramatta (Burnside Homes) 3.5 2.0 - - - - - 0.5 - - - - - - - - - 4.5 7.0 - - - - - - 10.5 3.0 24.0 1.5 0.5 -
North Rocks (Muirfield Golf Club) 8.5 3.0 - - - - - 1.0 - - - - - - - - - 8.5 10.5 0.5 - - - - - 17.0 4.0 39.5 2.5 0.5 -
Northmead Bowling Club 4.5 3.5 - - - - 0.5 1.0 - - - - - - 1.0 - - 4.5 6.5 - 0.5 0.5 - - - 10.0 3.0 24.0 2.0 - -
Parramatta (Baulkham Hills West (Sierra 0.5 5.5 - - - - - - - - - - - - - - - 4.5 6.0 0.5 - - - - - 9.0 1.5 28.0 1.5 - -
Penrith Lakes AWS
- - - - - - - - - -
- 0.6 0.6 - - 8.4 5.8 - - 0.2 - - - 12.8 2.2
0.8
-
Prospect Reservoir 1.1 5.8 - - - - - - 1.1 - - - - - - - - 9.2 5.4 - - 0.1 - - - 10.2 2.2 24.0 3.9 - 0.2
Richmond RAAF 5.2 0.6 - - - - - - - - -
- 1.4 - - - 6.0 6.4 0.2 - - - - - 10.0 0.8 24.6 0.2
-
Seven Hills (Radio FM 103.2) 0.5 4.5 - - 0.5 - - - 0.5 - - - - - - - - 10.0 4.5 0.5 - - - - - 7.0 1.0 26.0 1.5 - -
Seven Hills (Collins St) 0.8 5.5





1.0







7.2 5.8





10.0
27.0 0.6

St Clair (Juba Close) 3.0 1.0 - - - - - - 1.0 - - - - - - - - 5.0 6.0 - - - - - - 1.0 2.0 2.0
- -
Toongabbie Bowling Club 2.5 6.5 - 0.5 - - 1.5 - 0.5 - - - - - - - - 7.5 5.5 - - - - - - 9.0 1.5 25.5 2.0 - -
Toongabbie Ck (Redbank Road (Toongabbee 4.0 3.0 - -





0.5 - - - - - - 4.5 8.0 - - - - - - 11.0 2.0 26.0 2.0 - 0.5
West Pennant Hills (Cumberland S F Alert 5.5 3.5 - - - - - 1.5 - - - - - - - - - 12.0 7.5 - - - - - - 11.0 2.5 22.0 3.0 - -
Illawarra (68)12345678910111213141516171819202122232425262728293031
Camden Airport AWS 10.4 - - - - - - - 0.2 - - - - 0.4 - - - 3.6 2.6 - - - - - - 9.4 1.6 32.0 0.2 - -
Campbelltown (Kentlyn) 10.0 4.0 - - - - - - - - - - - - - - - 4.0 4.0 - - - - - - 7.0 1.0 22.0 - - -
Campbelltown (Mount Annan) 8.8 1.2 - - - - - - - - -
- 0.6 - - - 3.8 5.0 - - - - - - 8.8 0.8 26.4 0.2 - -
Rossmore (South Creek) 7.0 1.0 - - - - - - - - - - - - - - - 4.0 4.0 - - - - - - 11.0 - 26.0 - - -

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 11 am on Monday 4 January 2010. 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