Warm and dry Autumn

  • Below average rainfall.
  • Above average temperatures (maximum and minimum).

Rainfall

Sydney Observatory Hill recorded 249.6 mm in autumn which is below the historical average1 of 397.1 mm. The below average rainfall was mainly a product of well below average falls which were recorded in both March and April, despite good falls in the second half of May. The rain during autumn fell on 35 rain days which is below the historical average1 of 37 rain days. The dry conditions were due to the passage of several high pressure systems which brought mostly fine weather to Sydney. Much of the rainfall that did fall during autumn was restricted to coastal areas, resulting in much drier conditions in western parts of Sydney.

Sydney's storage levels at the start of autumn were at 59.3% and dropped to 56.3% at the end of May as much of the rainfall that fell in the Sydney basin was restricted to coastal areas. 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

Temperature

Warm conditions were recorded across the Sydney basin during autumn for both maximum and minimum temperatures. Sydney Observatory Hill recorded an average mean temperature (average of maximum and minimum temperatures) of 19.7°C which is 0.7°C above the historical average1 of 19.0°C. The passage of several high pressure systems throughout autumn brought mostly fine weather during the day resulting in above average maximum temperatures. Onshore winds and high humidity associated with the above average sea surface temperatures in Sydney contributed to the above average minimum temperatures. Very warm conditions persisted for the most part until the 17th of May with mostly cooler than normal conditions recorded for the remainder of autumn.

Maximum temperature

Sydney Observatory Hill recorded an average maximum temperature of 23.7°C which is 0.8°C above the historical average1 of 22.9°C. The warmest daily maximum temperature of 36.3°C was recorded at Sydney Airport on 21st March with the warmest average maximum temperatures for autumn of 24.8°C recorded at Penrith Lakes.

Minimum temperature

Sydney Observatory Hill recorded an average minimum temperature of 15.8°C which is 0.7°C above the historical average1 of 15.1°C. The warmest night of 23.0°C was recorded at Sydney Airport with the warmest nights on average recorded at Sydney Observatory Hill (15.8°C). The coldest night was -0.7°C recorded at both Richmond RAAF and Camden Airport AWS on 13th of May.

Wind

Prevailing winds in coastal Sydney during the afternoon (3pm) were between E and SE for 63% of the time during May (observations taken from Sydney Airport). The strongest wind gust of 81 km/hr was recorded at Sydney Airport on 21st March.

Other phenomena

Sydney recorded a total of 2 storms during autumn which is below the the historical average1 of 6 storms. Sunshine averaged at 6.7 hours per day which is above the historical average1 of 6.3 hours. On the morning of the 21st of April fog was observed at many locations across greater Sydney.

Further information

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Extremes in autumn 2010
Hottest day 36.3 °C at Sydney Airport AMO on 21 Mar
Warmest days on average 24.8 °C at Penrith Lakes AWS
Coolest days on average 22.3 °C at Terrey Hills AWS
Coldest day 13.7 °C at Terrey Hills AWS on 18 May
Coldest night -0.7 °C at Camden Airport AWS on 13 May
-0.7 °C at Richmond RAAF on 13 May
Coolest nights on average 10.8 °C at Camden Airport AWS
Warmest nights on average 15.8 °C at Sydney (Observatory Hill)
Warmest night 23.0 °C at Sydney Airport AMO on 29 Mar
Wettest overall

342.9 mm at Avalon Beach (Avalon (Palmgrove Rd))

Wettest day 98.0 mm at Ingleburn (Sackville Street) on 31 Mar
Highest wind gust 81 km/h at Sydney Airport AMO on 21 Mar




Summary statistics for autumn 2010
Maximum temperatures
for autumn
(°C)
Minimum temperatures
for autumn
(°C)
Rainfall
for autumn
(millimetres)
Mean for
autumn
2010
Diff
from
average
Highest for
autumn
2010
Mean for
autumn
2010
Diff
from
average
Lowest for
autumn
2010
Total for
autumn
2010
Average
for
autumn
Rank of
autumn
2010
Fraction of
autumn
average
Springwood Bowling Club 22.5   33.9 21 Mar 12.9   5.0 13 May 170.4 288.5 low 59%
Bankstown Airport AWS 24.1 +0.7 34.4 26 Mar 13.1 +0.3 4.3 13 May 200.2 251.3 average 80%
Canterbury Racecourse AWS 23.9   35.1 21 Mar 13.2   4.9 13 May 159.0
Holsworthy Control Range 24.3   35.8 21 Mar 12.2   3.6 6 May 119.0
Parramatta North (Masons Drive) 24.1 +0.6 35.2 21 Mar 13.1 +0.2 5.2 13 May 188.8 265.7 average 71%
Riverview Observatory 23.6 +1.1 34.5 21 Mar 13.7 +0.8 6.8 13 May 227.9 339.1 low 67%
Sydney (Observatory Hill) 23.7 +1.5 30.9 21 Mar 15.8 +1.2 9.0 13 May 249.6 375.8 average 66%
Sydney Airport AMO 23.8 +1.1 36.3 21 Mar 15.7 +1.5 7.9 13 May 244.8 320.1 average 76%
Sydney Olympic Park (Sydney Olympic Pk A 24.2   35.9 21 Mar 14.9   8.0 13 May 201.4
Terrey Hills AWS 22.3   33.0 26 Mar 14.1   6.1 13 May
Badgerys Creek AWS 24.4   35.1 26 Mar 11.3   2.0 13 May 132.2
Horsley Park Equestrian Centre AWS 24.2   34.9 21 Mar 12.8   3.6 13 May 112.0
Liverpool (Michael Wenden Centre) 24.7   35.5 21 Mar 12.0   1.6 27 Apr 175.6
Penrith Lakes AWS 24.8   36.0 21 Mar 13.0   3.5 13 May 95.4
Prospect Reservoir 24.5 +1.1 35.2 26 Mar 13.1 +0.1 4.1 13 May 175.7 241.7 average 73%
Richmond RAAF 24.2   35.1 21 Mar 11.5   -0.7 13 May 114.0
Camden Airport AWS 24.6 +0.9 35.2 21 Mar 10.8 -0.2 -0.7 13 May 161.8 208.0 average 78%
Campbelltown (Mount Annan) 24.7   35.2 21 Mar 11.3   1.0 13 May 134.0

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 10 am on Tuesday 1 June 2010. Some checks have been made on the data, but it is possible that results will change as new information becomes available.

A note about deciles: Deciles are used to give an element (in this case rainfall or temperature) a ranking. Deciles are calculated by arranging the totals in ascending order (from lowest to highest) then splitting them into 10 equal groups (thus the groups are called deciles). The first group would be in decile range one, the second group in decile range two, etc up to the highest annual totals (highest 10 per cent) being in decile range 10.

1Averages: Averages are based on the period 1961 to 1990 which is a convention of the World Meteorological Organisation

Normals are long-term averages 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 for temperature and less than 30 years of record for rainfall, as they cannot then be calculated reliably.

Further information

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