Greater Sydney in winter 2020: Near to above average temperatures and rainfall

Winter was fairly typical in 2020 for temperature, with both mean minimum and mean maximum temperature being close to or just above average. Rainfall was generally above average for most parts, mostly as a result of several significant rainfall events in July and August. These events also resulted in significant coastal erosion, snowfalls and damaging winds.

Near to above average rainfall

  • In general, rainfall in winter across Greater Sydney was near or above average, with totals ranging from 98% of average at Sydney Airport, to 168% of average at Mount Boyce in the Blue Mountains.
  • Most of Greater Sydney received below average rainfall in June, with few significant rainfall events affecting the area; in contrast, July and August both recorded above average rainfall, with several low pressure and frontal systems bringing wet and wintry conditions to the region.
  • The most significant event of winter was a result of a coastal low pressure system which developed on 26 July; the heaviest falls in Greater Sydney fell between the 26-28 July, with widespread 3 day totals exceeding 100 mm.
  • Other notable events included a Tasman low pressure system from 13-15 July which brought moderate shower activity to the area, but was more significant in terms of the large and powerful waves it produced; and a series of cold fronts and a complex low pressure systems from 7-10 August, which resulted in widespread three day totals of 50 mm to 80 mm.
  • There were 39 rain days at Sydney (Observatory Hill), just above average for winter (34 days).
  • Sunshine was typical for winter at Sydney Airport with 6.5 hours of bright sunshine on average per day.

Near to above average temperatures

  • Daytime temperatures were warmer than average in June and July, and close to average in August, resulting in the overall mean maximum temperature being slightly above average for winter.
  • Most sites were up to 1 °C warmer than average, but ranging from 0.3 °C below average at Cooranbong (Lake Macquarie AWS) to 1.6 °C above average at Katoomba (Farnells Rd).
  • The warmest winter day was on 30 August, where temperatures exceeded 25 °C across most Sydney basin sites; Badgerys Creek recorded 28.6 °C on this day, the warmest winter day for 2020.
  • The start of July also saw an unseasonably warm spell with daytime temperatures reaching the low to mid 20's on the 2nd.
  • Overnight temperatures were close to average in June and August, and above average in July, resulting in the overall mean minimum temperature being slightly above average for winter.
  • Most sites were up to up to 1 °C warmer than average, but ranging from 0.3 °C below average at Katoomba (Farnells Rd) and Mangrove Mountain to 1.6 °C above average at Sydney Airport.
  • The coldest night for winter was recorded on 25 August at Mount Boyce in the Blue Mountains, where the temperature dropped to -2.5 °C.

Sydney (Observatory Hill)

  • Total rainfall for Sydney (Observatory Hill) was 320.4 mm, which is 103% of the long-term average of 311.3 mm.
  • The mean daily maximum temperature for Sydney (Observatory Hill) was 18.6 °C, which is 1.5 °C above the long-term average of 17.1 °C.
  • The warmest day was 25.3 °C on 30 August, and the coolest day was on 7 August when the temperature reached 13.6 °C.
  • The mean daily minimum temperature for Sydney (Observatory Hill) was 9.7 °C, which is 0.9 °C above the long-term average of 8.8 °C.
  • The coldest morning was 6.3 °C on 5 August, and the warmest morning was on 1 June when the minimum temperature was 14.5 °C

Other phenomena

  • A deep low pressure system over the Tasman Sea generated very large and powerful waves along the NSW coast from 14 July, which resulted in hazardous beach conditions and coastal erosion, particularly along the coastal area near Wamberal. Peak waves exceeding 11.5 metres were recorded by the wave rider buoy offshore of Sydney. Wind gusts of 109 km/h were recorded at Wattamolla and 96km/h at Norah Head.
  • A significant rain event from 7-10 August and continued inflows after the event, saw Warragamba dam spill on the 16 August for the first time since July 2016. Levels had dropped to 42.7% in February 2020.
  • A vigorous cold front on 22 August brought snow to the Blue Mountains, with reports at Blackheath and Katoomba.

Further information

Media
(03) 9669 4057

Extremes in winter 2020
Hottest day 28.6 °C at Badgerys Creek AWS on 30 Aug
Warmest days on average 19.0 °C at Penrith Lakes AWS
Coolest days on average 10.8 °C at Mount Boyce AWS
Coldest day 2.9 °C at Mount Boyce AWS on 22 Aug
Coldest night -2.5 °C at Mount Boyce AWS on 25 Aug
Coolest nights on average 2.9 °C at Katoomba (Farnells Rd)
Warmest nights on average 11.4 °C at Sydney Harbour (Wedding Cake West)
Warmest night 16.5 °C at Sydney Harbour (Wedding Cake West) on 1 Jun
Warmest on average overall 14.6 °C at Sydney Harbour (Wedding Cake West)
Coolest on average overall 7.0 °C at Mount Boyce AWS
Wettest overall 379.7 mm at Randwick (Randwick St)
Wettest day 136.2 mm at Mangrove Mountain AWS on 27 Jul
Strongest wind gust 109 km/h at Wattamolla AWS on 14 Jul

Summary statistics for winter 2020
Maximum temperatures
(°C)
Minimum temperatures
(°C)
Rainfall
(millimetres)
Mean for
winter
2020
Diff
from
average
Highest for
winter
2020
Mean for
winter
2020
Diff
from
average
Lowest for
winter
2020
Total for
winter
2020
Average
for
winter
Rank of
winter
2020
Fraction of
winter
average
Badgerys Creek AWS 18.3 +0.1 28.6 30 Aug 5.6 +0.8 0.5 25 Aug 177.8 120.1 high 148%
Bankstown Airport AWS 18.6 +0.5 26.2 30 Aug 7.0 +1.0 2.3 25 Aug 234.8 174.1 high 135%
Camden Airport AWS 18.3 +0.2 25.4 30 Aug 4.9 +1.1 -1.2 27 Aug 177.0 146.1 high 121%
Campbelltown (Mount Annan) 18.5 +0.2 25.4 30 Aug 5.3 +0.6 -0.3 5 Aug 205.6 160.5 high 128%
Canterbury Racecourse AWS 18.4 +0.2 25.7 30 Aug 6.7 +0.3 1.7 25 Aug 274.0 228.7 average 120%
Cooranbong (Lake Macquarie AWS) 18.7 -0.3 25.2 30 Aug 5.9 +0.3 -0.6 27 Aug 313.4 212.5 high 147%
Gosford AWS 18.2   25.7 30 Aug 7.8   3.3 29 Aug 279.2
Holsworthy Aerodrome AWS 17.9   25.3 30 Aug 6.6   1.2 26 Aug 243.4
Holsworthy Defence AWS 17.3   25.0 30 Aug 6.8   2.2 26 Aug 293.0
Horsley Park Equestrian Centre AWS 17.9 -0.1 25.4 30 Aug 6.5 0.0 1.6 25 Aug 232.0 150.4 high 154%
Katoomba (Farnells Rd) 11.9 +1.6 19.0 29 Aug 2.9 -0.3 -1.7 5 Aug 333.7 279.0 high 120%
Mangrove Mountain AWS 17.0 +0.7 24.6 30 Aug 6.3 -0.3 0.6 6 Aug 327.8 217.8 high 151%
Mount Boyce AWS 10.8 +0.5 18.8 29 Aug 3.2 +0.1 -2.5 25 Aug 297.8 177.5 high 168%
Norah Head AWS 18.3 +0.2 24.2 31 Aug 10.7 +0.3 5.9 6 Aug 379.4 313.1 average 121%
Parramatta North (Masons Drive) 18.4 +0.3 25.5 30 Aug 7.1 +0.2 1.7 25 Aug 249.2 194.0 high 128%
Penrith Lakes AWS 19.0 +0.3 26.6 30 Aug 6.2 +0.1 0.7 6 Aug 178.4 107.6 high 166%
Richmond RAAF 18.7 +0.2 26.6 30 Aug 5.2 +0.8 -0.9 6 Aug 166.8 116.0 high 144%
Springwood (Valley Heights) 16.8 +0.1 24.5 30 Aug 7.4 +0.2 1.5 6 Aug 200.8 185.7 average 108%
Sydney (Observatory Hill) 18.6 +1.5 25.3 30 Aug 9.7 +0.9 6.3 5 Aug 320.4 311.3 average 103%
Sydney Airport AMO 18.5 +0.8 26.8 30 Aug 9.7 +1.6 6.2 25 Aug 263.4 269.5 average 98%
Sydney Harbour (Wedding Cake West) 17.9 +0.2 22.5 2 Jul 11.4 +0.4 7.6 5 Aug
Sydney Olympic Park AWS (Archery Centre) 18.8   26.5 30 Aug 7.3   2.6 25 Aug 236.6
Terrey Hills AWS 16.8 -0.1 24.3 30 Aug 8.4 +0.1 3.0 6 Aug 264.4 253.1 average 104%

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.

This summary includes 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 11 am on Tuesday 1 September 2020. 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

Climate