Greater Sydney in 2017: another warm year with a dry winter

Greater Sydney was warmer than average during 2017 for both daytime and overnight temperatures. The mean temperature at Observatory Hill was the second-warmest on record, behind 2016. Rainfall was average for the year, despite a dry winter and the driest September on record.

Average rainfall overall, but dry in the cooler months

  • Observatory Hill received slightly below average rainfall overall, with very dry conditions occurring over winter and early spring
  • Around 1075 mm was recorded at Observatory Hill, 89% of the long-term average
  • Rain fell on around 123 days, below the average of 141 days
  • Totals of 25 mm or more occurred on 17 days, above the average of 13 days; seven of these wet days occurred in March
  • The wettest day at Observatory Hill was recorded on 7 February when thunderstorms brought 85.0 mm in the 24 hours to 9 am on the 8th, including 31.4 mm in 30 minutes on the morning of the 7th
  • The wettest day across Greater Sydney was 7 June: a number of stations in the northwest received over 90 mm to in the 24 hours to 9am on the 8th
  • Above average rainfall was recorded in February, March and June, but the remaining months received average or below average totals
  • Observatory Hill had its driest September since observations began there in 1858, and the second driest July–September period

A hot start sets up a very warm year

  • Mean temperatures were above average across Greater Sydney; Observatory Hill had a mean annual temperature of 19.5 °C, 1.7 °C above average and the second-warmest on record behind 2016
  • The mean maximum at Observatory Hill was 23.7 °C, 2.0 °C above average and the equal second-warmest on record (tied with 2013 and behind 2016)
  • January 2017 was Sydney's warmest month ever recorded
  • Several stations set new records for warmest maxima and minima during January and February as part of several heatwaves that affected New South Wales
  • Several stations in Greater Sydney recorded temperatures over 45 °C on 11 February, including 47.0 °C at Richmond
  • Observatory Hill recorded 12 days of 35 °C or more, equalling the record set in 1926; several sites in the west reported a record number of days above 40 °C, including Richmond (15 days) and Parramatta North (12 days)
  • The annual mean minimum temperature at Observatory Hill was 15.2 °C; 1.4 °C above average; 2016 is the only year that has been warmer than this, and 2007, 2009 and 2014 were equally warm
  • A record number of 82 nights failed to drop below 20 °C at Observatory Hill, surpassing the previous record of 71 nights set in 2016

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Extremes in 2017
Hottest day 47.0 °C at Richmond RAAF on 11 Feb
Warmest days on average 25.6 °C at Richmond RAAF
Coolest days on average 18.3 °C at Mount Boyce AWS
Coldest day 4.7 °C at Mount Boyce AWS on 4 Aug
Coldest night -3.1 °C at Camden Airport AWS on 23 Jul
Coolest nights on average 8.5 °C at Mount Boyce AWS
Warmest nights on average 15.9 °C at Sydney Harbour (Wedding Cake West)
Warmest night 26.4 °C at Terrey Hills AWS on 31 Jan
Warmest on average overall 19.6 °C at Sydney Airport AMO
Coolest on average overall 13.4 °C at Mount Boyce AWS
Wettest overall 1427.2 mm at Berambing
Driest overall 508.0 mm at Milperra Bridge (Georges River)*
Wettest day 116.0 mm at Baulkham Hills Eucalyptus Ct on 8 Jun
Strongest wind gust 115 km/h at Wattamolla AWS on 7 Jun

* One day of rainfall data is missing, so the actual total might be slightly higher.


Record lowest annual total rainfall
New record
(mm)
Old
record
Years of
record
Annual
average
Sans Souci (Public School) 577.0 608.3 in 1936 115 1080.9



Record highest temperature
New record
(°C)
Old
record
Years of
record
Annual
average
Katoomba (Murri St) 37.7 on 11 Feb 37.6 on 8 Feb 2009 56 16.8
Mount Boyce AWS 37.2 on 11 Feb 36.2 on 8 Feb 2009 27 17.0
Richmond RAAF 47.0 on 11 Feb 46.4 on 18 Jan 2013 25 24.2
Mangrove Mountain AWS 44.4 on 11 Feb 43.6 on 18 Jan 2013 24 21.8
Badgerys Creek AWS 46.4 on 11 Feb 45.8 on 18 Jan 2013 23 23.9
Penrith Lakes AWS 46.9 on 11 Feb 46.5 on 18 Jan 2013 23 24.6



Record highest annual mean daily maximum temperature
New record
(°C)
Old
record
Years of
record
Annual
average
Sydney Airport AMO 24.1 = 24.1 in 2016 77 22.3
Parramatta North (Masons Drive) 24.5 = 24.5 in 1980 47 23.4
Mount Boyce AWS 18.3 18.2 in 2013 25 17.0
Richmond RAAF 25.6 25.4 in 2016 23 24.2
Mangrove Mountain AWS 23.3 = 23.3 in 2016 22 21.8
Canterbury Racecourse AWS 23.9 = 23.9 in 2016 20 23.0



Record highest daily minimum temperature
New record
(°C)
Old
record
Years of
record
Annual
average
Camden Airport AWS 24.3 on 14 Jan 24.0 on 3 Feb 2011 44 10.2
Mount Boyce AWS 24.5 on 11 Feb 24.3 on 14 Jan 2005 27 8.0
Richmond RAAF 26.2 on 31 Jan 25.0 on 23 Dec 2000 25 11.1
Mangrove Mountain AWS 26.2 on 20 Dec 25.7 on 2 Feb 2011 24 11.6
Badgerys Creek AWS 25.1 on 14 Jan 23.9 on 3 Feb 2011 23 10.8
Horsley Park Equestrian Centre AWS 25.0 on 20 Dec 24.7 on 3 Feb 2011 21 12.0



Highest annual mean daily minimum temperature for at least 20 years
Observed
(°C)
Most recent
higher
Annual
average
Prospect Reservoir 13.0 13.9 in 1990 12.3



Record highest annual mean temperature
New record
(°C)
Old
record
Years of
record
Annual
average
Mount Boyce AWS 13.4 13.3 in 2016 25 12.5
Mangrove Mountain AWS 17.6 = 17.6 in 2016 22 16.7
Richmond RAAF 18.6 = 18.6 in 2016 22 17.6
Canterbury Racecourse AWS 18.3 = 18.3 in 2016 20 17.7



Summary statistics for 2017
Maximum temperatures
(°C)
Minimum temperatures
(°C)
Rainfall
(millimetres)
Mean
for
2017
Diff
from
average
Highest
for
2017
Mean
for
2017
Diff
from
average
Lowest
for
2017
Total
for
2017
Average
annual
total
Rank
of
2017
Fraction
of annual
average
Badgerys Creek AWS 24.9 +1.0 46.4 11 Feb 11.5 +0.7 -1.4 23 Jul 639.0 680.9 average 94%
Bankstown Airport AWS 24.7 +1.4 44.5 10 Feb 12.6 +0.6 -0.9 23 Jul 641.6 871.8 low 74%
Camden Airport AWS 24.8 +1.1 45.6 11 Feb 10.9 +0.7 -3.1 23 Jul 597.8 788.0 low 76%
Campbelltown (Mount Annan) 24.7 +0.8 45.6 11 Feb 11.1 +0.4 -1.2 7 Jul 606.6
Canterbury Racecourse AWS 23.9 +0.9 43.1 10 Feb 12.8 +0.5 0.7 10 Jul
Cooranbong (Lake Macquarie AWS) 24.5   43.6 13 Jan 11.7   -0.5 3 Jul 839.8
Gosford AWS 23.7   41.9 5 Feb 13.6   2.3 3 Jul
Holsworthy Aerodrome AWS 24.2   45.1 11 Feb 11.8   -1.1 7 Jul 698.4
Horsley Park Equestrian Centre AWS 24.6 +0.9 44.5 11 Feb 12.6 +0.6 0.2 2 Jul 685.4 765.0 low 90%
Katoomba (Murri St) 18.7 +1.9 37.7 11 Feb 9.2 +1.2 -2.0 1 Jul 1266.0 1401.9 average 90%
Mangrove Mountain AWS 23.3 +1.5 44.4 11 Feb 11.8 +0.2 0.8 11 Jul 1148.0 1109.6 average 103%
Mount Boyce AWS 18.3 +1.3 37.2 11 Feb 8.5 +0.5 -2.2 28 Aug 1002.6 972.9 average 103%
Norah Head AWS 23.2 +1.0 39.9 24 Jan 15.6 +0.4 7.1 1 Jul 1016.2 1152.4 low 88%
Parramatta North (Masons Drive) 24.5 +1.1 44.5 10 Feb 12.4 +0.2 1.0 22 Jul 898.2 972.0 average 92%
Prospect Reservoir     43.4 13 Jan 13.0 +0.7 1.0 22 Jul 843.3 875.0 average 96%
Richmond RAAF 25.6 +1.4 47.0 11 Feb 11.7 +0.6 -2.1 22 Jul 675.8 738.1 low 92%
Sydney (Observatory Hill) 23.7 +2.0 39.4 31 Jan 15.2 +1.4 5.4 2 Jul 1075.6* 1214.8 average 89%
Sydney Airport AMO 24.1 +1.8 42.9 10 Feb 15.0 +1.5 4.9 2 Jul 874.4 1083.4 low 81%
Sydney Harbour (Wedding Cake West) 21.7 +0.4 37.9 31 Jan 15.9 +0.3 7.2 3 Jul
Sydney Olympic Park AWS (Archery Centre) 24.5   43.9 10 Feb 13.4   1.3 23 Jul
Terrey Hills AWS 22.5 +0.7 40.9 5 Feb 13.6 +0.4 2.9 30 May

* Rainfall data are missing for two days in October at Observatory Hill. Data from neighbouring sites suggest that the annual rainfall total might be 3 to 5 mm greater.


Notes

The Annual climate summary, generally published on the second working day of the year, lists the main features of the weather in Greater Sydney using the most timely and accurate information available on the date of publication; it will generally not be updated. More extensive discussion of significant weather events, along with later information and data that has had greater opportunity for quality control, will be presented in the Monthly Weather Review.

In September 2017 this summary was broadened to include data from observing sites in or near the Greater Sydney “Greater Capital City Statistical Area” (GCCSA). The Australian Bureau of Statistics designed the GCCSAs to “include the population within the urban area of the city, as well as people who regularly socialise, shop or work within the city, and live in small towns and rural areas surrounding the city. It is important to note that GCCSAs do not define the built up edge of the city. They provide a stable definition for these cities and are designed for the output of a range of social and economic survey data.

This statement has been prepared based on information available at 10 am on Tuesday 9 January 2018. Some checks have been made on the data, but it is possible that results will change as new information becomes available.

In some situations, some or all of the rainfall is in the form of hail or snow. In these cases the totals given are for the water equivalent: the depth of liquid water that results from melting any frozen precipitation. There can be significant 'undercatch' of snow in strong winds, meaning the true precipitation can be higher than that reported.

Averages for individual sites 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 10 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.

Where temperature area averages are mentioned, they are derived from the ACORN-SAT dataset.

Further information

Media
(03) 9669 4057
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