Thursday 1 March 2007 - Seasonal Climate Summary for Sydney - Product code IDCKGC25L0

Sydney has a mild summer with a rainy end

Mild days along the coast. Above average rainfall in western suburbs.

Details

  • Mild summer - average maximum temperatures lowest for 7 years
  • Slightly above average minimum temperatures
  • Above average rainfall in western suburbs, slightly below average in the east
  • Above average sunshine hours

Rainfall

The total summer rainfall of 227.2 mm at Observatory Hill was slightly below the historic summer average of 297.9 mm. There were 31 rain days, which is slightly below the historic average of 36 rain days.  Almost half the summer rainfall total fell during February (107.6 mm) with December and January receiving below average totals.  In a reversal of the usual pattern, the western suburbs received seasonal totals significantly higher than coastal suburbs, mainly due to the heavy rain in western Sydney during mid February.   The highest summer total was 330.8 mm at Berowra in Sydney's north followed by 314 mm at Campbelltown and Springwood in the far west.  The lowest was 201 mm at Sans Souci in the south.

Sydney's water catchments received above average rainfall during summer.  Warragamba Dam recorded a summer total of 350 mm and Woronora Dam 438 mm. The historic summer average is around 304 mm for both sites.

Temperature

Below average maximum temperatures were experienced in coastal Sydney during summer.   The average maximum (daytime) temperature at Observatory Hill was 25.5°C, which was below the historic average1 of 25.9°C.  This is the mildest summer since 1999−2000 when the average maximum temperature was 25.3°C.  Persistent cooling sea-breezes and frequent southerly changes contributed towards the mild conditions along the coast.  Average maximum temperatures in the western suburbs were about 3−4°C warmer than coastal suburbs.   There were only 4 hot days (temperature exceeding 30°C) at Sydney Observatory Hill during summer, only half the historic average of 8 hot days. In the western suburbs, Richmond recorded 37 hot days (historic average 38 days).

Average minimum (night-time) temperatures in Sydney were generally close to or slightly above the historic summer average. The average minimum at Observatory Hill of 19.3°C was 0.4°C above the historic average.  Average minimum temperatures in the western suburbs were about 2°C cooler than coastal suburbs and were close to the summer historic average.

The highest temperature at Sydney Observatory Hill during summer was 38.7°C on 21 January while the lowest temperature was 13.4°C on 4 December. Corresponding extremes across the Sydney metropolitan area ranged from 42.0°C at Badgerys Creek on 21 January to 7.0°C at Campbelltown and Holsworthy on 26 December.

Other phenomena

Sunshine hours were slightly above average during summer at 8.0 hours per day (historic average 7.6 hours per day).  There were 8thunderstorms recorded at Observatory Hill compared to the historic average of 9 storms for summer.  Thunderstorms at Penrith on 24 February produced wind squalls of 104 km/h. Flooding from thunderstorms in the Campbelltown area occurred twice during February, on the 12th and 28th (for more details see February climate summary for Sydney).

Further information

Mike De Salis
NSW Climate Services Centre
Bureau of Meteorology
Phone (02) 9296 1542
Email reqnsw@bom.gov.au

Extremes for Sydney area

Hottest day
Highest temperature
42.0°C at Badgerys Creek on 21 Jan 2007
Warmest days on average
Highest mean daily maximum temperature
30.3°C at Penrith
Coolest days on average
Lowest mean daily maximum temperature
25.5°C at Sydney (Observatory Hill)
Coldest day
Lowest daily maximum temperature
14.8°C at Springwood on 12 Dec 2006
Coldest night
Lowest temperature
7.0°C at Holsworthy and Campbelltown on 26 Dec 2006
Coolest nights on average
Lowest mean daily minimum temperature
15.7°C at Springwood
Warmest nights on average
Highest mean daily minimum temperature
19.3°C at Sydney (Observatory Hill)
Warmest night
Highest daily minimum temperature
22.8°C at Sydney (Observatory Hill) on 22 Jan 2007
22.8°C at Sydney Airport on 11 Feb 2007
Wettest overall
Highest total rainfall
330.8 mm at Berowra
Driest overall
Lowest total rainfall
201.0 mm at Sans Souci
Wettest day
Highest daily rainfall
103.6 mm at Badgerys Creek on 12 Feb 2007
Highest wind gust
104 km/h at Penrith on 24 Feb 2007

Summaries for Sydney area

Summary statistics for summer 2006−07
Maximum temperatures
for summer
(°C)
Minimum temperatures
for summer
(°C)
Rainfall
for summer
(millimetres)
Mean for
summer
2006−07
Diff
from
normal
Highest for
summer
2006−07
Mean for
summer
2006−07
Diff
from
normal
Lowest for
summer
2006−07
Total for
summer
2006−07
Normal
for
summer
Rank of
summer
2006−07
Fraction of
summer
normal
Sydney (Observatory Hill) 25.5 −0.4 38.7 21 Jan 2007 19.3 +0.4 13.4 4 Dec 2006 227.2 297.9 normal 76%
Parramatta 28.1 +0.2 41.0 21 Jan 2007 17.1 +0.1 9.8 17 Dec 2006 303.1 299.7 normal 101%
Richmond 29.6 +0.7 40.9 12 Jan 2007 17.0 −0.1 8.5 26 Dec 2006 287.6 270.6 normal 106%
Camden 29.2 +0.4 41.1 21 Jan 2007 16.5 +0.4 9.1 26 Dec 2006 278.4 231.9 normal 120%
Springwood 27.2 38.1 12 Jan 2007 15.7 8.2 26 Dec 2006 314.2 362.5 normal 87%
Terrey Hills* 26.1 39.7 21 Jan 2007 17.0 9.6 26 Dec 2006 216.0

* new station, no historic average temperatures available for Springwood and no historic average temperatures or average rainfall available for Terrey Hills

Summary phenomena for Sydney for summer 2006−07
 

Summer 2006−07

Normal for summer

Number of rain days

31

36

Average sunshine hours per day*

8.0

7.6

Average humidity at 3pm (%)

62

62

Number of thunderstorms

8

9

Number of windy days*

 28

17


Notes

This statement has been prepared based on information available at 12 pm on Thursday 1 March 2007. Some checks have been made on the data, but it is possible that results will change as new information becomes available.

1Averages: Historic average temperatures for Observatory Hill and Richmond are based on the period 1961 to 1990 which is a convention of the World Meteorological Organisation.  Average temperatures for Parramatta are based on all available data, 1968 - 2005 and Camden 1972 - 2005.  Rainfall averages and extremes for Observatory Hill are based on all years of record 1859 - 2005.

Normals 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 10 years of record, as they cannot then be calculated reliably.   The median is sometimes more representative than the mean of "normal" 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, normal in decile 4 to 7, high in decile 8 or 9 and very high is in decile 10). The Fraction of normal shows how much rain has fallen this time as a percentage of the long-term mean.