Sydney in August 2012: A warm, dry and sunny end to winter

  • Well below average rainfall
  • Equal 6th warmest August on record for maximum temperatures
  • Mild nights in the city, cool in the west
  • Most strong wind days since 2001

Dry end to winter

Sydney Observatory Hill recorded just 19 mm of rainfall during August, well below the historical average of 80.6 mm and the driest August since 2009 (6 mm). There were only four rain days during the month (average 10 days), with the highest falls reaching 10.2 mm on the 24th following thunderstorm activity. The only other major rain event during the month was due to coastal showers arising from an offshore low on the 11th and 12th, with falls of up to 12 mm at Avalon.

Warm days across the city, cool nights in the west

Sydney Observatory Hill recorded an average maximum temperature of 19.9 °C during August, 2.1 °C above the historical average. This is the equal sixth warmest August on record for Sydney, and the warmest since 20.9 °C in August 2009. Temperatures were above average across the city, associated with the dry, sunny conditions during the month.

Only one day in August fell below 15 °C, well below the average of 5 days, reaching 14.9 °C on the 10th, with 14 days reaching at least 20 °C (average 6 days). The warmest day reached 29.2 °C at Observatory Hill and 30 °C at the Airport on the 23rd during a spell of warm northwesterly winds, the 4th warmest August day on record at both sites.

The average minimum temperature at Sydney Observatory Hill was 9.4 °C, 0.5 °C above the historical average. Nights were generally above average in the eastern suburbs but cooler than average in the west, associated with generally clear conditions during the month. Parramatta recorded two nights of just 2.3 °C during the month, the coldest August nights since 1.8 °C on 19 August 2008.

The mean temperature for Sydney Observatory Hill was consequently 14.7 °C, 1.3 °C above the historical average.

Windiest August since 2001

The prevailing wind direction at Sydney Airport during August was WSW-NW, forming 42% of 3pm winds; only 19% of 3pm winds were SE-SW, below normal for August. There were seven strong wind days during August (average 4 days), the most in August since 8 days during 2001.

The first period of strong winds occurred between the 9th and 12th of the month, as a low pressure system developed off the coast in the wake of a passing front. The maximum wind gust at Sydney Airport reached 106 km/hr and 115 km/hr at Port Botany on the 11th, with wind speeds remaining above 50 km/hr for almost twelve hours and 10-minute mean wind speeds as high as 80 km/hr. The winds brought down trees and damaged roofs, as well as causing power outages across the city.

Strong winds were also recorded as a cold front crossed the state on the 16th and 17th, with further power outages and downed trees during gusts of up to 78 km/hr at the airport and 85 km/hr at Port Botany. Finally, wind gusts reached 89 km/hr at the airport and 91 km/hr at Fort Denison during thunderstorms on the 23rd, causing further downed trees, power outages and disruption to rail lines.

Above average sunshine

Sydney Airport recorded an average of 8.4 hours of bright sunshine during August, well above the historical average of 7.8 hours. There was one thunderstorm on the 23rd, the first storm since April, with no fog days reported at the airport.

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Extremes in August 2012
Hottest day 30.0 °C at Sydney Airport AMO on the 23rd
Warmest days on average 20.4 °C at Richmond RAAF
Coolest days on average 18.2 °C at Terrey Hills AWS
Coldest day 13.7 °C at Terrey Hills AWS on the 12th
Coldest night -2.8 °C at Camden Airport AWS on the 8th
Coolest nights on average 2.5 °C at Camden Airport AWS
Warmest nights on average 9.4 °C at Sydney (Observatory Hill)
Warmest night 16.1 °C at Sydney (Observatory Hill) on the 23rd
Warmest on average overall 14.6 °C at Sydney (Observatory Hill)
Coolest on average overall 11.0 °C at Camden Airport AWS
Wettest overall 23.0 mm at Avalon (Wollstonecraft Ave)
Wettest day 12.0 mm at Avalon (Wollstonecraft Ave) on the 11th
Highest wind gust 115 km/h at Port Botany (Molineux Point AWS) on the 10th

Summary statistics for August 2012
Maximum temperatures
for August
(°C)
Minimum temperatures
for August
(°C)
Rainfall
for August
(millimetres)
Mean for
August
2012
Diff
from
average
Highest for
August
2012
Mean for
August
2012
Diff
from
average
Lowest for
August
2012
Total for
August
2012
Average
for
August
Rank of
August
2012
Fraction of
August
average
Badgerys Creek AWS 19.8   28.8 23rd 3.7   -1.1 8th 3.2
Bankstown Airport AWS 20.0 +1.1 29.5 23rd 4.8 -1.2 0.6 4th 6.8 47.9 low 14%
Camden Airport AWS 19.5 +0.5 29.3 23rd 2.5 -1.4 -2.8 8th 3.4 42.4 v low 8%
Campbelltown (Mount Annan) 19.5   28.9 23rd 3.1   -1.2 8th 5.0
Canterbury Racecourse AWS 19.4   29.0 23rd 5.6   0.4 8th 7.2
Holsworthy Control Range 19.5   28.9 23rd 3.9   -0.7 5th 7.0
Horsley Park Equestrian Centre AWS 19.5   28.4 23rd 5.2   0.1 7th 8.6
Liverpool (Michael Wenden Centre) 20.0   28.9 23rd 4.1   0.2 4th 7.8
Parramatta North (Masons Drive) 19.5 +0.5 29.1 23rd 6.5 -0.6 2.3 2nd 9.8 54.4 low 18%
Penrith Lakes AWS 20.2   28.9 23rd 5.1   0.7 8th 5.0
Prospect Reservoir     28.7 23rd 6.3 -0.5 1.7 8th 5.6 49.8 v low 11%
Richmond RAAF 20.4   29.4 23rd 3.0   -2.4 8th 4.8
Riverview Observatory 19.4 +1.1 28.7 23rd 6.9 -0.3 3.0 8th 13.5 70.1 low 19%
Springwood (Valley Heights) 18.4   26.5 23rd 6.4   2.2 7th 8.4 53.4 low 16%
Sydney (Observatory Hill) 19.9 +2.1 29.2 23rd 9.4 +0.5 5.6 8th 19.0 80.3 low 24%
Sydney Airport AMO 19.9 +1.6 30.0 23rd 8.8 +0.7 5.7 8th 12.6 75.5 low 17%
Terrey Hills AWS 18.2   27.9 23rd 7.8   3.6 8th 15.4

Notes

A Monthly 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 8 am on Monday 3 September 2012. 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