Thursday 3 January 2008 - Annual Climate Summary for Sydney extremes - Product code IDCKGC3xx0

 

Year 2007: Sydney has record warm nights

Summary

• Average annual minimum temperature was highest in 149 years of record
• Many warm nights, total of 61 nights when minimum temperature exceeded 20°C (3rd highest on record)
• 12th consecutive year with average or above average maximum temperatures
• 11th consecutive year with above average minimum temperatures
• Wettest year since 1998
• Stormiest year since 1963
• Slightly above average sunshine hours

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Rainfall

Sydney's total annual rainfall of 1499.2 mm recorded at Observatory Hill, was above the historic annual average of 1215 mm and ranks in the highest 20% of totals.  It was the wettest year in Sydney since 1998 (when 1649 mm recorded). There were 133 rain days during the year which is slightly below the historic average of 138 rain days.  About half the annual rainfall (730 mm) occurred during Sydney's wet winter, with the majority of the winter total falling in June. The western suburbs were drier than the coast but still close to the historic average. Annual rainfall extremes ranged from 1672 mm at Turramurra on the north shore to 929 mm at Box Hill in the north west and 947.2 mm at Campbelltown in the far south west.

The above average annual rainfall can be attributed to Sydney's very wet winter and the above average rainfall in November and December, resulting from a late establishing La Nina event in the Pacific Ocean.

Sydney's Warragamba Dam catchment also received above average rainfall during 2007 with totals ranging from 1155 mm in the lower catchment to 639 mm at Goulburn Airport in the upper catchment. Over the year storage capacity rose from 36% in early January to 61% at the end of December.

Maximum temperatures

Sydney experienced generally mild to warm days during 2007. The average maximum (daytime) temperature at Observatory Hill was 22.7°C, significantly above the historic average¹ of 22.1°C and ranks as equal 9th warmest year since records commenced in 1859. Average maximum temperatures in the western suburbs were about 1°C warmer than coastal suburbs due mainly to the absence of cooling sea-breezes during the warmer months.

While Sydney recorded significantly above average maximum temperatures during most months of 2007, June was the noteable exception recording well below average temperatures (the coldest June for 18 years). The above average temperatures in Sydney are consistent with above average temperatures experienced throughout NSW. Sydney has now experienced 12 consecutive years with average or above average maximum temperatures. This is a pattern consistent with the observed global trend of rising temperatures.

The highest temperature at Sydney Observatory Hill during 2007 was 38.7°C on 21 January while the highest in the Sydney metropolitan area was 42.0°C at Badgerys Creek also on 21 January.

Minimum temperatures

Average minimum (night-time) temperatures at Sydney Observatory Hill were well above the historic average¹ during 2007.  The average minimum of 15.2°C was 1.0°C above the historic average¹. This is the warmest average annual minimum temperature on record for Sydney since records commenced in 1859. The previous highest was 15.1°C in 1988. This is now the 11th consecutive year at Observatory Hill with above average minimum temperatures. Sydney's western suburbs recorded annual minimum temperatures several degrees cooler than along the coast but still significantly above the historic average. Sydney Airport recorded its highest average annual minimum temperature on record with 15.0°C, the previous highest was 14.9°C in 1998.

Warm nights persisted from January to March and again in December. There were 61 nights when the temperature did not fall below 20°C, the 3rd highest ever recorded. Normally Sydney would expect only 36 nights above 20°C (based on standard normal period 1961−1990).

The lowest temperature at Sydney Observatory Hill during 2007 was 3.7°C on 17 July while the lowest in the Sydney metropolitan area was −3.5°C at Badgerys Creek also on 17 July.

Wind

There were 75 strong wind days recorded at Sydney Airport during 2007 compared to the historic average of 63 days. Only 6 gales were recorded during the year (average 11 gales). The highest wind gust in metropolitan Sydney during 2007 was 109 km/h from the west at Camden on 5 March. The prevailing direction at coastal sites was NW-NE for about 40% of the time.

Other phenomena

Thunderstorms: Sydney recorded 33 thunderstorms during 2007 compared to the historic average of 28 storms. This is the highest number of storms since 1963 when 51storms were recorded. One of the most severe storms occurred on 4 April when 96 mm was recorded at Rose Bay with marble size hail and major local flooding of houses and shops. However, the most severe was the supercell of 9 December which produced heavy rain, squally winds and giant hail up to 7cm size from Blacktown to Wahroonga with unconfirmed reports of 11cm size hail in Cherrybrook. The total damage bill was close to $200 million. The period from about 19 November to 10 December was Sydney's most stormy and humid 3 week spell for about 20 years with many reports of local flash flooding during storms, especially in inner west suburbs.

Bushfires: burnt out several hundred hectares of bushland in Ku-ring-gai Chase National Park north of Sydney during January and October, however, there were no reports of property being destroyed.

Further information

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

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Extremes for the Sydney area

Hottest day Highest temperature	42.0°C at Badgerys Creek on 21 Jan
Warmest days on average Highest mean daily maximum temperature	24.5°C at Penrith Lakes
Coolest days on average Lowest mean daily maximum temperature	21.9°C at Terrey Hills
Coldest day Lowest daily maximum temperature	10.8°C at Springwood on 27 Jun and 19 Aug
Coldest night Lowest temperature	−3.5°C at Badgerys Creek on 17 Jul
Coolest nights on average Lowest mean daily minimum temperature	10.8°C at Campbelltown (Mount Annan)
Warmest nights on average Highest mean daily minimum temperature	15.2°C at Sydney (Observatory Hill)
Warmest night Highest daily minimum temperature	23.0°C at Sydney Olympic Park on 22 Jan 23.0°C at Sydney (Observatory Hill) on 4 Mar
Wettest overall Highest total rainfall	1671.7 mm at Turramurra and 1666.6 mm at Castle Cove
Driest overall Lowest total rainfall	929.0 mm at Box Hill and 947.2 mm at Campbelltown (Mount Annan)
Wettest day Highest daily rainfall	156.6 mm at Ruse on 11 Feb
Highest wind gust	109 km/h at Camden Airport on 5 Mar

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Records

Record highest annual mean daily minimum temperature
	Mean daily minimum temperature for 2007 (°C)	Previous annual highest		Years of record	Normal annual
Sydney Airport	15.0	14.9	in 1998	78	13.1
Sydney (Observatory Hill)	15.2	15.1	in 1988	149	14.2

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Record lowest annual temperature
	Lowest temperature in 2007 (°C)		Previous annual lowest		Years of record	Normal annual
Prospect Dam	−0.6	on 17 Jul	−0.5	in 2005	43	12.2

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Summaries for the Sydney area

Summary statistics for 2007
	Maximum temperatures (°C)				Minimum temperatures (°C)				Rainfall (millimetres)
	Mean for 2007	Diff from normal	Highest for 2007		Mean for 2007	Diff from normal	Lowest for 2007		Total for 2007	Normal annual total	Rank of 2007	Fraction of annual normal
Sydney (Observatory Hill)	22.7	+0.6	38.7	21 Jan	15.2	+1.0	3.7	17 Jul	1499.2	1215.4	high	123%
Camden Airport	23.8	+0.2	41.1	21 Jan	10.9	+0.7	−3.1	17 Jul	1023.4	771.0	high	133%
Parramatta North	23.7	+0.5	41.0	21 Jan	12.9	+0.8	0.0	17 Jul	1370.6	963.9	very high	142%
Richmnd	23.7	0.0	40.9	12 Jan	11.6	+0.5	−3.4	17 Jul	1051.2	810.3	high	130%
Springwood*	22.2		38.1	12 Jan	11.5		−2.6	17 Jul	1188.7	1067.5	normal	111%
Terrey Hills*	21.9		39.7	21 Jan	13.3		0.2	17 Jul	1302.2

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

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Additional climate data for Sydney for Year 2007
	Year 2007	Normal for year
Number of rain days	133	138
Average sunshine hours per day*	7.4	7.2
Average humidity at 3pm (%)	57	57
Number of thunderstorms	33	28
Number of windy days*	75	63
Number of gales*	6	11

* recorded at Sydney Airport.  Windy day defined as average speed of 40−62 km/h or more at synoptic times and gale 63−87 km/hr.

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Notes

 

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