Monday 3 December 2007 - Seasonal Climate Summary for Sydney extremes - Product code IDCKGC2xx0

Sydney has warmest spring nights on record

Summary

  • warm spring, average maximum temperature was 1.0°C above historic average
  • 12 consecutive springs with above average maximum temperatures
  • numerous warm days with 29 days above 25°C (normally only 18 days)
  • very warm nights, average minimum temperature of 15.3°C was highest ever recorded in spring
  • Nine out of last 10 years have recorded above average minimum temperatures in spring
  • numerous warm nights; 46 nights when temperature did not fall below 15°C (normally 29 nights above 15°C)
  • slightly above average rainfall
  • plentiful sunshine

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Rainfall

The total spring rainfall of 238.2 mm at Sydney (Observatory Hill) was slightly above the historic spring average1 of 229.2 mm. Most of this spring's rain occurred during November (170 mm) which could be contributed to a delayed rainfall response of the La Nina event established since August in the Pacific Ocean. There were 29 rain days, which is below the historic average of 33 rain days. The highest spring rainfall totals were in the north shore area of Sydney while the lowest were in southern suburbs. Totals ranged from a high of 286.0 mm at West Pymble to a low of 161.2 mm at Sydney Airport.  

Sydney's Warragamba Dam catchment area recorded spring rainfall totals of 200−260 mm in the lower catchment which is a little above the normal spring rainfall in this area. In the upper catchment (Goulburn area) totals of around 140 mm were slightly below the normal spring rainfall.

Temperatures

Days were generally warm and sunny in Sydney during spring.  The average maximum (daytime) temperature at Observatory Hill was 23.1°C, which is 1.0°C above the historic spring average1 of 22.1°C and ranks 13th warmest in 149 years of record.  Above average spring temperatures were recorded over the entire metropolitan area.

This is now the 12th consecutive spring with above average maximum temperatures in Sydney. The last 'cool' spring was in 1995 with below average temperatures.

Sydney's nights were also very warm for spring. The average minimum temperature at Observatory Hill of 15.3°C was 1.4°C above the historic spring average1 of 13.9°C. This is the highest average minimum temperature on record in Sydney for spring. Previous highest was 15.1°C in 1988. Sydney experienced persistent very mild nights during spring, a total of 46 nights with a minimum temperature above 15°C. Normally Sydney would expect around 29 nights above 15°C in spring. Although average minimum temperatures in the western suburbs were several degrees cooler than coastal suburbs (up to 5°C cooler at Camden), they were still well above the historic spring average at all recording sites.

Sydney has now experienced nine out of the last 10 years with above average minimum temperatures in spring.

The highest temperature at Sydney Observatory Hill during spring was 34.8°C on 3 October while the lowest temperature was 8.8°C on 23 September.  Corresponding extremes across the Sydney metropolitan area ranged from a high of 36.2°C at Sydney Airport on 3 October to a low of 2.0°C at Campbelltown on 23 September.

Wind

There were 15 windy days in coastal Sydney during spring, compared to the historic average of 18 windy days. The prevailing coastal wind direction was from S to E with around 60% of all winds in this quadrant during spring. The highest wind gust in the Sydney metropolitan area was 93 km/h at Sydney Olympic Park on 30 September.

Other phenomena

Hot, dry conditions in late September and much of October caused numerous days of very high bushfire danger with several bushfires reported around Sydney. There were 2 severe storms during October, one on 12 October producing 4cm hail at Camden Airport, and the other on 26 October when heavy rain and local flash flooding caused power outages in the Ryde area. Sunshine was abundant with an average of 8.3 hours per day, the sunniest spring for 5 years.

Further information

Mike De Salis
NSW Climate Services Centre
Bureau of Meteorology
Phone (02) 9296 1555
Email mikede@bom.gov.au

Extremes for the Sydney area

Hottest day
Highest temperature		 36.2°C at Sydney Airport on 3 Oct
Warmest days on average
Highest mean daily maximum temperature		 25.6°C at Penrith Lakes
Coolest days on average
Lowest mean daily maximum temperature		 22.4°C at Terrey Hills
Coldest day
Lowest daily maximum temperature		 13.1°C at Springwood on 4 Sep and on 6 Sep
Coldest night
Lowest temperature		 2.0°C at Campbelltown (Mount Annan) on 23 Sep
Coolest nights on average
Lowest mean daily minimum temperature		 10.5°C at Camden Airport and Campbelltown (Mount Annan)
Warmest nights on average
Highest mean daily minimum temperature		 15.3°C at Sydney (Observatory Hill)
Warmest night
Highest daily minimum temperature		 21.6°C at Parramatta and Sydney Airport on 29 Oct
Wettest overall
Highest total rainfall		 286.0 mm at West Pymble
Driest overall
Lowest total rainfall		 161.2 mm at Sydney Airport
Wettest day
Highest daily rainfall		77.0 mm at Abbotsbury (Fairfield City Farm) on 27 Nov
Highest wind gust
 93 km/h at Sydney Olympic Park on 30 Sep

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Records

Record highest spring mean daily minimum temperature
Mean daily minimum
temperature
for spring 2007 (°C) 		Previous highest
for spring		 Years of
record		 Normal for
spring
Sydney (Observatory Hill)
15.3
 15.1 in 1988
149
13.9
Sydney Airport AMO
15.0
 14.9 in 2005
69
12.8

 

Summaries for the Sydney area

Summary statistics for Spring 2007
Maximum temperatures
for Spring
(°C)		 Minimum temperatures
for Spring
(°C)		 Rainfall
for Spring
(millimetres)
Mean for
Spring
2007		 Diff
from
normal		 Highest for
Spring
2007		 Mean for
Spring
2007		 Diff
from
normal		 Lowest for
Spring
2007		 Total for
Spring
2007		 Normal
for
Spring		 Rank of
Spring
2007		 Fraction of
Spring
normal
Sydney (Observatory Hill)
23.1
+1.0
 34.8 3 Oct
15.3
+1.4
 8.8 23 Sep 238.2 229.2 normal
104%
Camden Airport
24.8
+0.9
 34.4 3 Oct
10.5
+0.7
 2.3 23 Sep 205.0 179.7 normal
114%
Parramatta
24.4
+1.2
 35.0 3 Oct
12.6
+1.2
 5.8 10 Sep 258.2 206.3 normal
125%
Richmond
24.9
+0.7
 34.7 3 Oct
11.7
+1.2
 3.4 23 Sep 186.6 180.4 normal
103%
Springwood*
23.3
33.4 22 Oct
11.1
3.5 23 Sep 229.2 226.5 normal
101%
Terrey Hills*
22.4
34.0 3 Oct
13.3
7.2 13 Oct 239.0

* new stations, no historic average temperatures available and no historic average rainfall available for Terrey Hills.

Additional climate data for Sydney (Observatory Hill) for Spring 2007
 

Spring 2007

Normal for Spring

Number of rain days
29
33

Average sunshine hours per day*
8.3
7.8

Average humidity at 3pm (%)
54
55

Number of thunderstorms
9
8

Number of windy days*
15
18

* recorded at Sydney Airport

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Notes

This statement has been prepared based on information available at 11 am on Monday 3 December 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 - 2006 and Camden 1972 - 2006.  Rainfall averages and extremes for Observatory Hill are based on all years of record 1859 - 2006.

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.