Year 2009: Very warm with below average rainfall in Sydney

  • Below average rainfall
  • Well above average maximum temperatures
  • 17th consecutive year with above average annual maximum temperatures
  • Well above average minimum temperatures, 2nd highest in record
  • Sydney had several severe storms and one severe duststorm
  • Close to average annual sunshine

Rainfall

Sydney's total annual rainfall of 956.2 mm recorded at Observatory Hill, was below the historical annual average of 1214 mm or 79% of the normal annual rainfall. The wettest period was autumn and early winter with above average rainfall in both April and May. October was the wettest month (180 mm) and August was the driest (6 mm), followed by November (13 mm). Sydney's wettest day was caused by a severe thunderstorm on 26 October with 73 mm at Observatory Hill and 119.4 mm at Frenchs Forest. There were 122 rain days during the year which is well below the historic average of 144 and the lowest since 2005.

The western suburbs were drier than the coast and also experienced generally below average rainfall, however, the Bankstown area recorded close to average rainfall. Annual rainfall extremes ranged from 1237.7 mm at St Ives on the North Shore, to 537.6 mm at Penrith in the far west.

Sydney's Warragamba Dam catchment received below average rainfall during 2009 with totals ranging from around 615 mm in the lower catchment to 491 mm at Goulburn in the upper catchment. Due to the dry year, water levels fell significantly from 63% of capacity in early January to 53% at the end of December. 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 generally warm days during 2009. The average annual maximum (daytime) temperature at Observatory Hill was 22.9 °C, or 0.9 °C above the historical annual average1. This ranks as 7th highest annual average maximum temperature since records commenced in 1859. It is now the 17th consecutive year with above average annual maximum temperatures at Observatory Hill. Similar conditions prevailed in western Sydney with well above average maximum temperatures (see table below). The very high temperatures experienced throughout the second half of 2009 are likely due to the influence of the 2009 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 2009 was 40.9 °C on 24 January while the highest in the Sydney metropolitan area was 43.3 °C at Penrith on 15 January.

Average minimum (night-time) temperatures at Sydney Observatory Hill of 15.1 °C were well above (+1.2 °C) the historical average1 during 2009. This is equal second highest in the 151 years of record, and the same as 1988. The warmest year for minimum temperatures was 2007 with an average of 15.2 °C.

Observatory Hill recorded 118 warm nights during the year (minimum temperature greater than 18 °C), only one day short of the all time highest, 119 warm nights in 2006. Normally Sydney would expect around 76 warm nights. Sydney's western suburbs recorded annual minimum temperatures several degrees cooler than along the coast but were still well above the historical average (see table below).

The lowest temperature at Sydney Observatory Hill during 2009 was 5.9 °C on 9 August while the lowest in the Sydney metropolitan area was -2.8 °C at Camden Airport also on 9 August.

Some sites had their highest mean daily maximum temperature on record. Some sites had their highest mean daily maximum temperature for at least 20 years. Some sites had their highest mean daily minimum temperature for at least 20 years.

Wind

Prevailing wind directions were NE-NW (45% of the time) and from the S-SE (25% of the time). There were 72 strong wind* days recorded at Sydney Airport during 2009 compared to the historical average of 63 days. This includes one westerly gale on 14 October associated with a strong cold front. The highest wind gust in metropolitan Sydney during 2009 was 94 km/hr at Penrith Lakes AWS caused by a thunderstorm on 20 November. However, a gust of 117 km/hr was recorded at Wattamolla AWS (Royal National Park, south of Sydney) on the 8th October caused by an east coast low pressure system.

Other phenomena

Thunderstorms: Sydney recorded 27 thunderstorms during 2009, very close to the historical average of 26 storms. One of the more severe was on 21st February, with Avalon Beach in Sydney's north recording 77 mm in about 2 hours, flash flooding at Parramatta and Berowra with golf ball size hail at Cowan. A storm on 2nd May caused heavy rain and flash flooding in the eastern suburbs. Very heavy rain on 25th October associated with slow moving thunderstorms caused flash flooding in parts of the inner west and North Shore, the Royal National Park and Earlwood. The highest 24 hour rainfall was 119.4 mm at Frenchs Forest.

Duststorms: Because of the very dry conditions over inland NSW, Sydney experienced 8 days with duststorms or significant raised dust (visibility below 10 km), compared to the normal 3 days. The majority occurred during September and November. A major duststorm with strong winds hit Sydney during the morning of 23rd September producing a blood red sky and reducing visibility to 400 metres over much of the city. A thick layer of red dust coated all exposed surfaces with many flights delayed or cancelled at Sydney Airport. It was Sydney's worst duststorm since 1942.

Sunshine: The amount of sunshine in Sydney during 2009 averaged 7.3 hours per day which is very close to the historic average of 7.2 hours per day.  However, monthly averages varied considerably, from 5.1 hours per day in June to a very sunny 9.1 hours per day in January, the highest for January for 15 years.

* strong wind days defined as average wind speed of 40 km/hr or more over a 10 minute period.

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Extremes in 2009
Hottest day 43.3 °C at Penrith Lakes AWS on 15 Jan
Warmest days on average 25.3 °C at Penrith Lakes AWS
Coolest days on average 22.1 °C at Terrey Hills AWS
Coldest day 11.0 °C at Bankstown Airport AWS on 14 Jun
Coldest night -2.8 °C at Camden Airport AWS on 9 Aug
Coolest nights on average 10.7 °C at Camden Airport AWS
Warmest nights on average 15.1 °C at Sydney (Observatory Hill)
Warmest night 25.9 °C at Prospect Reservoir and Sydney Olympic Park on 24 Jan
Wettest overall 1237.7 mm at St Ives (Richmond Avenue)
1124.0 mm at Avalon (Wollstonecraft Ave)
Driest overall 537.6 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 annual mean daily maximum temperature
Mean daily maximum
temperature
for 2009 (°C)
Previous annual
highest
Years of
record
Annual
average
Sydney Airport 23.4 = 23.4 in 2005 69 22.2

Highest annual mean daily maximum temperature for at least 20 years
Mean daily maximum
temperature
for 2009 (°C)
Most recent higher
annual
Years since
higher
Annual
average
Camden Airport AWS 24.6 25.1 in 1980 22 23.6



Highest annual mean daily minimum temperature for at least 20 years
Mean daily minimum
temperature
for 2009 (°C)
Most recent higher
annual
Years since
higher
Annual
average
Parramatta North 12.9 13.0 in 1973 35 12.1


Summary statistics for 2009
Maximum temperatures
(°C)
Minimum temperatures
(°C)
Rainfall
(millimetres)
Mean
for
2009
Diff
from
average
Highest
for
2009
Mean
for
2009
Diff
from
average
Lowest
for
2009
Total
for
2009
Average
annual
total
Rank
of
2009
Fraction
of annual
average
Sydney (Observatory Hill) 22.9 +0.9 40.9 24 Jan 15.1 +1.4 5.9 9 Aug 956.2 1214.4 low 79%
Bankstown Airport AWS 23.9 +0.8 41.5 20 Nov 12.5 +0.5 1.3 9 Aug 823.8 875.9 average 94%
Camden Airport AWS 24.6 +1.0 43.1 17 Dec 10.7 +0.6 -2.8 9 Aug 617.2 783.7 low 79%
Liverpool 24.6 +1.4 42.0 17 Dec 11.6 0.0 -1.2 9 Aug 697.7 865.0 low 81%
Parramatta North 24.1 +0.8 41.8 17 Dec 12.9 +0.8 2.4 9 Aug 820.9 962.8 low 85%
Penrith Lakes AWS 25.3   43.3 15 Jan 12.6   1.5 6 Jul 537.6
Richmond RAAF 24.7 +1.0 42.1 17 Dec 11.6 +0.6 -2.4 11 Jun 578.2 809.6 low 71%
Terrey Hills AWS 22.1   39.2 24 Jan 13.6   3.1 6 Jul 968.4

Notes

The Annual 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 9 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. For Observatory Hill, averages1 are calculated for the period 1918-2009.
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