Sydney in summer 2012-13: A warm summer with a wet end

  • Above average temperatures
  • Wettest summer since 2007/8
  • Hottest day on record
  • Wettest day since March 2012

Rainfall

Sydney Observatory Hill recorded 348.4 mm of rain during summer, slightly above the historical average of 297.3 mm and the wettest summer since 2007/8. The rain fell over 36 days, average for summer, with four days recording at least 25 mm (average 3 days). The first half of summer was generally dry, with only 54.4 mm recorded in the 57 days to January 26, including less than 10 mm during the first three weeks of January; this was the driest start to a summer since 1982.

The second half of summer featured several significant rainfall events, resulting in above average rainfall for both January and February. Ex-Tropical Cyclone Oswald caused heavy falls across the Sydney basin between the 27th and 29th of January, with 3-day totals of up to 204.4 mm at Belrose and daily totals of up to 161 mm at Castle Cove on the 29th. Sydney Observatory Hill recorded 95.2 mm on the 29th, its wettest day since 8 March 2012.

This was followed by further rain across the city during February, with a surface trough and embedded low producing falls of up to 74.8 mm at Dover Heights on the 2nd, while an East Coast Low produced falls of up to 81 mm at Audley on the 24th. As a result of the late summer rain events Warragamba Dam reached full capacity during late February. Current water storage information can be found on the Bureau of Meteorology Water Storage web site.

Temperature

Sydney Observatory Hill recorded an average maximum temperature of 26.6 °C during summer, 1.0 °C above the historical average, with above average maximum temperatures throughout the city. Days were generally warmer than average during the first half of summer, including temperatures 1.8 °C above normal during January, but closer to average during February when rainfall was higher. There were 8 days when temperatures reached at least 30 °C, average for Sydney, but 25 days that reached at least 28 °C (average 16). In western Sydney, Richmond recorded 18 days greater than 35 °C, the most since 2005.

The warmest period was during the first half of January, when a large scale heatwave impacted much of Australia, described in Special Climate Statement 43. Temperatures reached 42.3 °C at Sydney Observatory Hill on the 8th, its fifth highest temperature on record, before setting a new record maximum temperature of 45.8 °C on the 18th. Fourteen stations across the city reached at least 45 °C on this day, with the coolest (Terrey Hills) recording 43.9 °C and the warmest (Penrith) 46.5 °C; all seven stations with long-term records were at least 0.5 °C warmer than the previous record.

Minimum temperatures were also above average across the city, with 19.6 °C at Sydney Observatory Hill, 1.2 °C above the historical average. Minimums were well above average throughout the season, with 45 nights above 20 °C (average 21) and only four of 15 °C or below (average 7). The mean daily temperature at Sydney Observatory Hill was consequently 23.1 °C, 1.1 °C above the historical average

Some sites had their highest summer temperature on record.

Other phenomena

The prevailing wind direction at Sydney Airport was southerly, with 43% of 9am winds and 39% of 3pm winds between SE and SSW, normal for summer. Winds at 9am were between N and NE 33% of the time, above the historical average of 22%. There was an average of 7.2 hours of bright sunshine at the airport during the season, slightly below the historical average of 7.5 hours, with cloudiest conditions during December.

Six thunderstorms were reported at Sydney Airport during summer (average 9 storms), with 14 storms anywhere in the metropolitan region. Low pressure systems caused heavy rain, flash flooding and strong winds between 27-29 January and 23-24 February, while wind gusts reached 104 km/h at Terrey Hills during a cold change on 18 January.

Further information

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Extremes in summer 2012-13
Hottest day 46.5 °C at Penrith Lakes AWS on 18 Jan 2013
Warmest days on average 29.9 °C at Penrith Lakes AWS
29.9 °C at Richmond RAAF
Coolest days on average 26.0 °C at Terrey Hills AWS
Coldest day 16.4 °C at Springwood (Valley Heights) on 10 Dec 2012
Coldest night 7.0 °C at Camden Airport AWS on 6 Dec 2012
Coolest nights on average 16.4 °C at Springwood (Valley Heights)
Warmest nights on average 19.6 °C at Sydney Airport AMO
Warmest night 24.0 °C at Bankstown Airport AWS on 26 Jan 2013
Warmest on average overall 24.0 °C at Penrith Lakes AWS
Coolest on average overall 21.9 °C at Springwood (Valley Heights)
21.9 °C at Terrey Hills AWS
Wettest overall 452.6 mm at Turramurra (Kissing Point Road)
Wettest day 161.0 mm at Castle Cove (Rosebridge Ave) on 29 Jan 2013
Highest wind gust 104 km/h at Terrey Hills AWS on 18 Jan 2013

Record highest summer temperature
Highest temperature
in summer 2012-13 (°C)
Previous warmest
for summer
Years of
record
Average for
summer
Sydney (Observatory Hill) 45.8 on 18 Jan 2013 45.3 on 14 Jan 1939 155 25.6
Sydney Airport AMO 46.4 on 18 Jan 2013 45.2 on 1 Jan 2006 74 26.2
Prospect Reservoir 45.1 on 18 Jan 2013 44.7 on 15 Jan 2001 48 27.9
Parramatta North (Masons Drive) 45.5 on 18 Jan 2013 44.8 on 1 Jan 2006 46 27.9
Bankstown Airport AWS 46.1 on 18 Jan 2013 44.8 on 18 Jan 2003 45 27.7
Camden Airport AWS 46.4 on 18 Jan 2013 45.0 on 30 Jan 2003 38 28.8
Riverview Observatory 45.4 on 18 Jan 2013 44.0 on 1 Jan 2006 30 26.2


Summary statistics for summer 2012-13
Maximum temperatures
for summer
(°C)
Minimum temperatures
for summer
(°C)
Rainfall
for summer
(millimetres)
Mean for
summer
2012-13
Diff
from
average
Highest for
summer
2012-13
Mean for
summer
2012-13
Diff
from
average
Lowest for
summer
2012-13
Total for
summer
2012-13
Average
for
summer
Rank of
summer
2012-13
Fraction of
summer
average
Badgerys Creek AWS 29.2   45.8 18 Jan 2013 17.0   8.2 6 Dec 2012 366.8
Bankstown Airport AWS 28.5 +0.8 46.1 18 Jan 2013 18.1 +0.5 10.2 6 Dec 2012 298.4 267.2 average 112%
Camden Airport AWS 29.4 +0.6 46.4 18 Jan 2013 16.7 +0.5 7.0 6 Dec 2012 290.8 242.0 average 120%
Campbelltown (Mount Annan) 28.6   45.0 18 Jan 2013 16.5   7.1 6 Dec 2012 369.2
Canterbury Racecourse AWS 27.0   44.6 18 Jan 2013 17.8   9.6 6 Dec 2012 369.6
Holsworthy Aerodrome AWS 28.2   45.8 18 Jan 2013 17.6   8.3 6 Dec 2012 307.2
Holsworthy Control Range 28.2   45.7 18 Jan 2013 16.9   8.2 6 Dec 2012 312.2
Horsley Park Equestrian Centre AWS 28.8   44.9 18 Jan 2013 17.3   9.8 6 Dec 2012 335.6
Parramatta North (Masons Drive) 28.2 +0.3 45.5 18 Jan 2013 17.3 +0.2 9.6 6 Dec 2012 301.8 304.3 average 99%
Penrith Lakes AWS 29.9   46.5 18 Jan 2013 18.1   10.5 6 Dec 2012 327.2
Prospect Reservoir 28.6 +0.7 45.1 18 Jan 2013 17.6 +0.3 10.5 6 Dec 2012 339.7 265.6 high 128%
Richmond RAAF 29.9   46.4 18 Jan 2013 17.4   8.1 6 Dec 2012 344.4
Springwood (Valley Heights) 27.4   44.1 18 Jan 2013 16.4   10.0 6 Dec 2012 414.6 368.2 average 113%
Sydney (Observatory Hill) 26.6 +1.0 45.8 18 Jan 2013 19.5 +1.2 14.0 6 Dec 2012 348.4 297.7 average 117%
Sydney Airport AMO 27.2 +1.0 46.4 18 Jan 2013 19.6 +1.2 14.4 6 Dec 2012 311.0 281.6 average 110%
Terrey Hills AWS 26.0   43.9 18 Jan 2013 17.7   11.6 6 Dec 2012 382.0

Notes

A Seasonal Climate Summary is prepared to list the main features of the weather in 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 Friday 1 March 2013. 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