Greater Sydney in winter 2017: a warm and dry winter across the region

Winter in the Greater Sydney region was drier than average overall, and Sydney's driest since 2009. Days were warmer than average, although similar to last winter. Average to cooler than average minimum temperatures were widespread inland, although warmer than average overnight temperatures dominated closer to the coast.

This summary includes data from observing sites in or near the Greater Sydney “Greater Capital City Statistical Area” (GCCSA) – see the notes.

Wet June, dry in July and August

  • Winter was drier than average overall for Sydney, although above average rainfall in June kept seasonal totals closer to average in the west; Observatory Hill recorded 211.4 mm of rain for the season, below the average of 312.0 mm and the driest winter since 2009
  • Observatory Hill received rainfall on 22 days during winter, much less than the average of 34 days, while rain fell in Parramatta North on 17 days, compared to an average of 28 days
  • There were five days when 10 mm or more fell at the Sydney Observatory, below the average of eight days, and at least 10 mm of rain fell in Parramatta North on four occassions, slightly below the long-term average of five days
  • The heaviest rainfalls came at the start of the season, with all days with totals of 25 mm or more occurring in June
  • Sunshine was slightly above average for winter, with a cloudy June but sunny July and August

Warm days but cooler mornings in the west

  • Maximum temperatures were above average for winter across Sydney; The mean daily maximum temperature for Sydney (Observatory Hill) was 18.9 °C, the equal seventh-warmest on record and equal to winter 2016
  • The end of July was particularly warm, with many stations across the city recording their warmest July day on record on the 30th
  • Observatory Hill recorded 25 days above 20 °C during the season and Parramatta North recorded 24 days, both of which are more than average but similar to the number of warm winter days in recent years
  • Minimum temperatures at Observatory Hill were above the long-term average, but were slightly colder than average in the suburbs; winter minimum temperatures for Parramatta North were 6.4 °C for winter, 0.6 °C colder than average
  • There were also more warm nights than average in the city centre, although fewer than average in the west; Observatory Hill reported 33 minimum temperatures above 10 °C (more than the average of 26), while Parramatta North reported 12 nights (below the average of 15)

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Extremes in winter 2017
Hottest day 29.3 °C at Cooranbong (Lake Macquarie AWS) on 11 Aug
Warmest days on average 19.3 °C at Cooranbong (Lake Macquarie AWS)
Coolest days on average 11.0 °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 2.8 °C at Mount Boyce AWS
Warmest nights on average 10.9 °C at Sydney Harbour (Wedding Cake West)
Warmest night 17.5 °C at Norah Head AWS on 31 Jul
Warmest on average overall 14.6 °C at Norah Head AWS
Coolest on average overall 6.9 °C at Mount Boyce AWS
Wettest overall 266.4 mm at Dover Heights (Portland St)
Driest overall 71.0 mm at Rossmore (South Creek)
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
Record highest winter daily minimum temperature
New record
(°C)
Old
record
Years of
record
Average for
winter
Norah Head AWS 17.5 on 31 Jul 17.3 on 20 Jul 2016 23 10.4



Summary statistics for winter 2017
Maximum temperatures
(°C)
Minimum temperatures
(°C)
Rainfall
(millimetres)
Mean for
winter
2017
Diff
from
average
Highest for
winter
2017
Mean for
winter
2017
Diff
from
average
Lowest for
winter
2017
Total for
winter
2017
Average
for
winter
Rank of
winter
2017
Fraction of
winter
average
Badgerys Creek AWS 18.5 +0.4 27.0 30 Jul 4.6 -0.2 -1.4 23 Jul 77.8 122.1 average 64%
Bankstown Airport AWS 18.9 +0.9 26.8 30 Jul 5.5 -0.5 -0.9 23 Jul 129.6 175.8 average 74%
Camden Airport AWS 18.5 +0.5 27.0 30 Jul 3.1 -0.7 -3.1 23 Jul 93.4 149.0 low 63%
Campbelltown (Mount Annan) 18.5 +0.4 27.1 30 Jul 4.1 -0.8 -1.2 7 Jul 99.8 171.3 low 58%
Canterbury Racecourse AWS 18.5 +0.3 26.1 30 Jul 6.2 -0.3 0.7 10 Jul 138.0 232.9 low 59%
Cooranbong (Lake Macquarie AWS) 19.3   29.3 11 Aug 5.2   -0.5 3 Jul 84.4
Gosford AWS 18.5   27.0 11 Aug 7.6   2.3 3 Jul
Holsworthy Aerodrome AWS 18.3   26.5 30 Jul 5.0   -1.1 7 Jul 103.4
Horsley Park Equestrian Centre AWS 18.3 +0.3 27.3 30 Jul 6.4 -0.1 0.2 2 Jul 96.6 153.8 average 63%
Katoomba (Murri St) 12.3 +2.1 18.6 30 Jul 3.8 +0.6 -2.0 1 Jul 141.4 280.0 average 51%
Mangrove Mountain AWS 17.1 +0.9 25.4 11 Aug 5.9 -0.7 0.8 11 Jul 147.6 212.2 average 70%
Mount Boyce AWS 11.0 +0.7 17.7 15 Aug 2.8 -0.3 -2.2 28 Aug 101.4 177.7 low 57%
Norah Head AWS 18.6 +0.5 27.6 11 Aug 10.7 +0.3 7.1 1 Jul 206.6 301.6 average 69%
Parramatta North (Masons Drive) 18.7 +0.6 26.8 30 Jul 6.4 -0.6 1.0 22 Jul 213.8 195.5 average 109%
Prospect Reservoir 18.3 +0.6 27.1 30 Jul 6.6 -0.2 1.0 22 Jul 116.6 183.3 average 64%
Richmond RAAF 19.0 +0.6 27.9 30 Jul 4.1 -0.4 -2.1 22 Jul 139.6 118.7 high 118%
Springwood (Valley Heights) 17.1 +0.5 25.9 30 Jul 7.6 +0.5 3.5 1 Jul 90.9 187.4 average 49%
Sydney (Observatory Hill) 18.9 +1.8 26.5 30 Jul 9.4 +0.6 5.4 2 Jul 211.4 311.4 average 68%
Sydney Airport AMO 19.0 +1.3 27.0 30 Jul 9.1 +1.0 4.9 2 Jul 158.8 270.6 low 59%
Sydney Harbour (Wedding Cake West) 17.8 +0.2 24.8 30 Jul 10.9 -0.2 7.2 3 Jul
Sydney Olympic Park AWS (Archery Centre) 19.0   26.7 30 Jul 6.7   1.3 23 Jul 190.8
Terrey Hills AWS 17.0 +0.2 24.6 11 Aug 8.1 -0.2 3.3 22 Jul 172.8 262.3 low 66%

Notes

The Seasonal climate summary, generally published on the first working day of each month, 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 Friday 1 September 2017. 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
Enquiries