Spring nights warmest on record in Sydney

  • Very warm nights - highest average minimum temperature on record
  • 24 warm nights (minimum greater than 18 °C), highest on record
  • 8th warmest average maximum temperature
  • Slightly below average rainfall
  • Average sunshine

Rainfall

Sydney metropolitan area recorded slightly below average rainfall during spring. Observatory Hill's total of 209.4 mm for the season compares to historic average1 of 230 mm. Over 86% of Sydney's spring rain fell in about 3 weeks in October with September and November remaining very dry. There were only 26 rain days during the season, well below the historic spring average of 35 rain days. The wettest suburbs in spring were in Sydney's north, the highest total being 265 mm at North Rocks in northwest Sydney. The driest region was the far west where the lowest total for the season was 79.4 mm at Penrith Lakes AWS. The wettest single day was 119.4 mm at Frenchs Forest on 26 October.

The majority of Sydney's spring rainfall fell during October associated with moist onshore winds. Both September and November recorded less than 20 mm each and were associated with the stabilising effect of persistent high pressure systems.

Sydney's Warragamba Dam catchment area recorded below average spring rainfall with most totals between 100 and 140 mm over the catchment area. Storage levels have fallen over spring from 59% on 1 September to currently 55% of total 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

Sydney experienced a very warm spring with above average temperatures over the whole of the metropolitan area. The average maximum (daytime) temperature at Observatory Hill during spring was 23.5 °C, which is 1.6 °C above the historic average1 of 22.9 °C. It ranks as Sydney's 8th warmest spring out of 150 years of record. Sydney's warmest spring was in 2002 (average maximum 24.2 °C). Maximum temperatures were a few degrees warmer in the western suburbs. Both Prospect Reservoir (42.0 °C) and Riverview Observatory (40.5 °C) set new records for their highest spring temperature.

Sydney's spring nights were the warmest ever recorded. The average minimum at Observatory Hill of 15.4 °C was 2.0 °C above the historic spring average1 of 13.4 °C. The previous highest average spring minimum temperature was 15.3 °C set in 2007. There was also 24 warm nights during spring (minimum greater than 18 °C), the highest ever recorded at Observatory Hill. During a typical spring there is normally only 7 nights above 18 °C. Record high minimums were not confined to the coast with numerous inland suburbs also reporting record high average spring minimums. The above average temperatures were mostly due to only weak cool changes reaching Sydney, especially in September and November, and heatwave conditions in November caused by a slow moving high pressure system.

An El Niño event is currently maturing in the equatorial Pacific Ocean.  These events are usually (but not always) associated with above average temperatures in eastern Australia. Very high temperatures experienced throughout winter and spring are likely due to the current influence of El Niño combined with the background, long-term warming that has been observed across Australia since the start of last century.

The highest temperature at Sydney Observatory Hill during spring was 40.4 °C on 22 November while the highest over the Greater Sydney area was 42.5 °C at Sydney Airport also on 22 November. The lowest temperature at Observatory Hill during spring was 8.9 °C on 10 October while the lowest over the Greater Sydney area was 2.0 °C at Camden Airport AWS also on 10 and 11 September and at Campbelltown on 11 September.

Some sites had their highest spring temperature on record. Some sites had their warmest spring night (highest daily minimum temperature) on record. Some sites had their highest spring mean daily minimum temperature on record.

Wind

The prevailing afternoon wind direction in coastal Sydney during spring was E-NE for 50% of the time, above the normal frequency of 42% from this direction. The strongest wind gust was 94 km/h at Penrith Lakes AWS on 20 November during a thunderstorm.

Other phenomena

A major duststorm with strong winds hit Sydney during the morning of 23 September producing a blood red sky and reducing visibility to 400 metres over much of the city. The dust, originating from South Australia and western NSW, was the worst duststorm in Sydney since 1942. Sydney had 12 thunderstorms during spring (historic average 9 storms). Very heavy rain on 25 October associated with slow moving thunderstorms caused flash flooding in parts of the inner west, North Shore, Audley Weir and Wolli Creek at Earlwood. On 20 November, two houses caught fire after being struck by lightning during a severe thunderstorm. A downburst from the same storm caused extensive damage to houses at Church Point in northern Sydney.

Sydney recorded a spring average of 7.8 hours of sunshine per day, which is normal for the season. However, this was a combination of plentiful sunshine in September (average 8.8 hours per day) and cloudy conditions in October (average 6.8 hours per day).

Further information

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Extremes in spring 2009
Hottest day 42.5 °C at Sydney Airport AMO on 22 Nov
Warmest days on average 27.2 °C at Penrith Lakes AWS
Coolest days on average 22.8 °C at Terrey Hills AWS
Coldest day 13.1 °C at Terrey Hills AWS on 3 Oct
Coldest night 2.0 °C at Camden Airport AWS on 10 Sep
2.0 °C at Camden Airport AWS on 11 Sep
2.0 °C at Campbelltown (Mount Annan) on 11 Sep
Coolest nights on average 11.0 °C at Camden Airport AWS
11.0 °C at Campbelltown (Mount Annan)
Warmest nights on average 15.4 °C at Sydney (Observatory Hill)
Warmest night 23.1 °C at Penrith Lakes AWS on 21 Nov
Wettest overall 265.0 mm at North Rocks
237.7 mm at Castle Cove
Driest overall 79.4 mm at Penrith Lakes AWS
Wettest day 119.4 mm at Frenchs Forest on 26 Oct
Highest wind gust 94 km/h at Penrith Lakes AWS on 20 Nov

Record highest spring temperature
Highest temperature
in spring 2009 (°C)
Previous highest
for spring
Years of
record
Average for
spring
Prospect Reservoir 42.0 on 20 Nov 41.6 on 25 Nov 2002 44 23.4
Riverview Observatory 40.5 on 22 Nov = 40.5 on 25 Nov 2002 27 22.5



Record highest spring daily minimum temperature
Highest daily minimum
temperature
in spring 2009 (°C)
Previous highest
for spring
Years of
record
Average for
spring
Camden Airport AWS 21.7 on 21 Nov 21.0 on 4 Nov 2005 34 9.8



Record highest spring mean daily minimum temperature
Mean daily minimum
temperature
for spring 2009 (°C)
Previous highest
for spring
Years of
record
Average for
spring
Sydney (Observatory Hill) 15.4 15.3 in 2007 150 13.4
Sydney Airport 15.2 14.9 in 2007 70 12.9
Bankstown Airport AWS 12.8 12.7 in 2005 41 11.5
Parramatta North 13.1 12.9 in 2005 41 11.7



Summary statistics for spring 2009
Maximum temperatures
for spring
(°C)
Minimum temperatures
for spring
(°C)
Rainfall
for spring
(millimetres)
Mean for
spring
2009
Diff
from
average
Highest for
spring
2009
Mean for
spring
2009
Diff
from
average
Lowest for
spring
2009
Total for
spring
2009
Average
for
spring
Rank of
spring
2009
Fraction of
spring
average
Sydney (Observatory Hill) 23.5 +1.6 40.4 22 Nov 15.4 +2.0 8.9 10 Oct 209.4 229.7 average 91%
Bankstown Airport AWS 24.8 +1.4 41.5 20 Nov 12.8 +1.3 4.2 10 Sep 151.0 182.6 average 83%
Camden Airport AWS 25.5 +1.6 41.9 20 Nov 11.0 +1.2 2.0 10 Sep 121.8 180.6 average 67%
Liverpool 25.6 +2.1 41.6 20 Nov 11.8 +0.6 3.2 11 Sep 131.1 184.4 average 71%
Parramatta North 24.9 +1.3 41.8 20 Nov 13.1 +1.4 6.0 17 Oct 177.8 208.2 average 85%
Penrith Lakes AWS 27.2   42.2 20 Nov 12.8   4.2 11 Sep 79.4
Richmond RAAF 25.9 +1.6 41.4 22 Nov 11.9 +1.2 2.1 11 Sep * 179.7 - -
Springwood 24.2   42.0 20 Nov 12.4   6.1 11 Sep 150.2 226.1 low 66%
Sydney Airport 24.2 +1.9 42.5 22 Nov 15.2 +2.3 8.7 11 Sep 181.2 212.4 average 85%
Terrey Hills AWS 22.8   38.9 20 Nov 13.7   7.8 1 Sep 156.8

* incomplete record, total rainfall not available.


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 11 am on Tuesday 1 December 2009. 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