Monday, 3 September 2012 - Monthly Climate Summary for Sydney - Product code IDCKGC25L0
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.
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.
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.
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.
|Extremes in August 2012|
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|
13.7 °C at Terrey Hills AWS on the 12th|
-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)|
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|
23.0 mm at Avalon (Wollstonecraft Ave)|
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|
|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%|
|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|
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
(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.