Greater Sydney in 2020: wettest year in over 20 years

It was a wet year in Greater Sydney, with annual rainfall the highest since 1998 in the central city and since 1990 in many western suburbs. After an extremely hot start to the year, temperatures were above average but not as high as those of 2019.

A wet year in Greater Sydney

  • Rainfall in 2020 was above average throughout Greater Sydney.
  • At most locations, rainfall was 20% to 50% above the long-term average, although some coastal locations were closer to average.
  • Some sites had their highest daily rainfall on record.
  • Some sites, mostly sites which opened in the 1990s, had their highest total rainfall on record.
  • Some sites had their highest total rainfall for at least 20 years. In particular, some locations in western Sydney had their wettest year since 1990.
  • February was especially wet throughout Greater Sydney, with most sites receiving three to four times their average monthly rainfall. At Observatory Hill, it was the fourth-wettest February on record and the wettest month since June 2007.
  • July was also significantly wetter than average.
  • April was a very dry month, with Observatory Hill rainfall 77% below average, although the Aprils of 2018 and 2019 were even drier. September was also significantly drier than average.
  • After February, seasonal rainfall was relatively close to average. Autumn, winter and spring were all within 20% of average at Observatory Hill, with autumn and spring slightly below average and winter slightly above.

Nights warmer than average

  • Night-time minimum temperatures were above average in 2020 at most Greater Sydney locations, while daytime maximum temperatures were near average in the west and generally above average near the coast.
  • Most sites were in the order of 0.5 °C above average for minimum temperatures, although larger differences from average occurred at some locations.
  • Daytime maximum temperatures were generally cooler than those in 2019, whilst night-time minimum temperatures were similar to those of 2019.
  • January was a hot month, with maximum temperatures 3 °C or more above average at some locations.
  • Nights were warm in spring, with some sites, particularly in western Sydney, having their highest average spring minimum temperatures on record.
  • Autumn was relatively cool, particularly in March. Average minimum temperatures at Observatory Hill for both March and autumn were the lowest since 2008, while March was the first month with minimum temperatures below the long-term average there since April 2017.
  • Some sites had their highest temperature on record.
  • Some sites had their warmest night (highest daily minimum temperature) on record.
  • Some sites had their highest mean daily minimum temperature on record.
  • Some sites in western Sydney had their highest mean daily minimum temperature for at least 20 years.

Sydney (Observatory Hill)

  • Rainfall measured for 2020 at Sydney (Observatory Hill) was 1551.2 mm, 28% above the long-term average at the former Observatory Hill site.
  • The exact total for 2020 is not known due to an equipment outage in September. Based on totals recorded during the outage at surrounding sites, it is estimated that 5 to 10 mm fell during the outage period in addition to the measured total of 1551.2 mm.
  • This is the wettest year at this location since 1998.
  • The mean daily maximum temperature for Sydney (Observatory Hill) was 23.5 °C.
  • This is 1.7 °C above the long-term average at the former Observatory Hill site, but cooler than 2018 or 2019.
  • The warmest day was 41.2 °C on 23 January, 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 14.7 °C.
  • This is 0.9 °C above the long-term average at the former Observatory Hill site.
  • The coldest morning was 6.2 °C on 25 August, and the warmest morning was on 29 November when the minimum temperature was 25.3 °C.

A summer of heatwaves and floods

  • Extreme heat affected Greater Sydney on a number of occasions early in the year. The most exceptional heat was on 4 January, when temperatures reached 48.9 °C at Penrith, the highest temperature ever recorded in Greater Sydney.
  • Later in the year, on 28 and 29 November, Observatory Hill exceeded 40 °C on 2 successive days, only the second time this has occurred at that location at any time of year. Some Western Sydney sites experienced their hottest night on record on the 29th.
  • Major fires which were burning in and around the Greater Sydney region at the end of 2019, continued through the first few weeks of 2020, until heavy rain fell in early February. Significant smoke pollution affected parts of the region at times.
  • Heavy rain from 7 to 10 February resulted in significant flooding in parts of Greater Sydney. There was major flooding in the Hawkesbury-Nepean and Georges Rivers, with the Hawkesbury at North Richmond reaching its highest level since 1992.
  • During the February event, Observatory Hill had 242.0 mm of rain in two days and 391.6 mm in four days, the highest such totals for any month since 1992 and 1990 respectively.
  • A major hailstorm affected parts of Greater Sydney on 20 January, with hailstones of up to 6 cm in diameter and widespread damage reported.
  • Several coastal lows affected eastern New South Wales in July and August. Whilst the most severe impacts were in the Illawarra and South Coast districts, Greater Sydney experienced heavy rain, particularly from 26 to 28 July, and some coastal erosion.
  • The most significant snow of the winter in the Blue Mountains was on 22 August, with light falls reported at Blackheath and Katoomba.

Further information

Media
(03) 9669 4057

Extremes in 2020
Hottest day 48.9 °C at Penrith Lakes AWS on 4 Jan
Warmest days on average 24.8 °C at Penrith Lakes AWS
Coolest days on average 17.4 °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 7.7 °C at Katoomba (Farnells Rd)
Warmest nights on average 15.9 °C at Sydney Harbour (Wedding Cake West)
Warmest night 28.1 °C at Bankstown Airport AWS on 29 Nov
Warmest on average overall 19.2 °C at Norah Head AWS
19.2 °C at Sydney Airport AMO
Coolest on average overall 12.9 °C at Mount Boyce AWS
Wettest overall 2015.7 mm at Katoomba (Farnells Rd)
Wettest day 296.0 mm at Oakdale (Cooyong Park) on 10 Feb
Strongest wind gust 115 km/h at Camden Airport AWS on 25 Sep

Record highest daily rainfall
New record
(mm)
Old
record
Years of
record
Picton Council Depot 260.0 on 10 Feb 245.9 on 9 Nov 1966 135
Camden Airport AWS 181.6 on 10 Feb 156.0 on 3 Feb 1990 49
Peakhurst Golf Club 225.0 on 10 Feb 173.8 on 6 Aug 1986 46
Oakdale (Cooyong Park) 296.0 on 10 Feb 208.0 on 12 Jun 1964 44
Chatswood Bowling Club 206.0 on 10 Feb 191.0 on 10 Feb 1956 32
Badgerys Creek AWS 200.0 on 10 Feb 138.0 on 31 Jan 2001 26
Canterbury Racecourse AWS 189.2 on 10 Feb 128.0 on 31 Jan 2001 26
Oyster Bay (Green Point Road) 174.0 on 10 Feb 156.0 on 5 Feb 2002 23
St Ives (Richmond Avenue) 187.6 on 10 Feb 178.6 on 20 Mar 2011 23
Baulkham Hills Eucalyptus Ct 147.0 on 10 Feb 121.0 on 21 Apr 2015 21
Concord (Brays Rd) 166.6 on 10 Feb 124.0 on 21 Apr 2015 21
North Parramatta (Burnside Homes) 171.0 on 10 Feb 164.0 on 5 Jun 2016 21
North Rocks (Muirfield Golf Club) 154.5 on 10 Feb 154.0 on 18 Apr 2005 21
Seven Hills (Radio FM 103.2) 144.5 on 10 Feb 111.0 on 6 Jun 2016 21
Wyong (Mount Elliot) 229.0 on 8 Feb 166.0 on 29 Jan 2013 21
Faulconbridge (Great Western Hwy) 241.0 on 10 Feb 134.0 on 29 Jan 2013 20
Greystanes (Bathurst Street) 147.0 on 10 Feb 126.6 on 6 Jun 2016 20



Record highest annual total rainfall
New record
(mm)
Old
record
Years of
record
Annual
average
Peakhurst Golf Club 1318.0 1247.9 in 1974 36 891.0
Mount Boyce AWS 1585.6 1435.6 in 2007 26 984.7
Penrith Lakes AWS 1094.2 1013.4 in 2007 24 721.6
Horsley Park Equestrian Centre AWS 1283.4 1071.2 in 2007 23 771.7

Highest annual total rainfall for at least 20 years
Observed
(mm)
Most recent
higher
Annual
average
Springwood (Valley Heights) 1545.8 1585.6 in 1974* 1082.0
Katoomba (Farnells Rd) 2015.7 2088.8 in 1978* 1404.3
Bankstown Airport AWS 1113.8 1343.1 in 1990* 871.3
Prospect Reservoir 1282.0 1388.1 in 1990* 876.8
Kurrajong Heights (Bells Line of Road) 1627.0 1827.8 in 1990* 1243.1
Camden (Brownlow Hill) 1026.6 1250.6 in 1990* 740.6
Audley (Royal National Park) 1484.0 1669.4 in 1990* 1096.9
Faulconbridge (St Georges Crescent) 1577.7 1963.3 in 1990* 1131.0
Yarramalong (Lewensbrook) 1523.8 1856.6 in 1990* 1112.7
Camden Airport AWS 1081.8 1183.3 in 1990* 789.8
Mount Wilson (Clarine) 1810.2 1866.6 in 1988* 1272.7

* note: there are gaps in the historical record at this site, so it is possible a higher value has gone unreported




Record highest temperature
New record
(°C)
Old
record
Years of
record
Annual
average
Katoomba (Farnells Rd) 39.8 on 4 Jan 39.5 on 21 Dec 2019 59 16.9
Parramatta North (Masons Drive) 47.0 on 4 Jan 45.5 on 18 Jan 2013 54 23.4
Bankstown Airport AWS 47.0 on 4 Jan 46.1 on 18 Jan 2013 53 23.4
Mount Boyce AWS 38.0 on 1 Feb 37.5 on 21 Dec 2019 30 17.1
Richmond RAAF 47.4 on 4 Jan 47.0 on 11 Feb 2017 28 24.3
Badgerys Creek AWS 47.6 on 4 Jan 46.4 on 11 Feb 2017 26 24.0
Canterbury Racecourse AWS 45.9 on 4 Jan 44.9 on 7 Jan 2018 26 23.1
Penrith Lakes AWS 48.9 on 4 Jan 47.3 on 7 Jan 2018 26 24.8
Horsley Park Equestrian Centre AWS 47.0 on 4 Jan 45.6 on 7 Jan 2018 24 23.9



Record highest daily minimum temperature
New record
(°C)
Old
record
Years of
record
Annual
average
Bankstown Airport AWS 28.1 on 29 Nov 26.0 on 2 Feb 2011 53 12.1
Camden Airport AWS 25.1 on 29 Nov 24.3 on 14 Jan 2017 47 10.2
Mount Boyce AWS 26.1 on 2 Feb 24.5 on 11 Feb 2017 30 8.1
Badgerys Creek AWS 26.1 on 29 Nov 25.1 on 14 Jan 2017 26 10.9
Penrith Lakes AWS 26.2 on 2 Feb 25.7 on 3 Feb 2011 26 12.4
Horsley Park Equestrian Centre AWS 27.4 on 29 Nov 25.0 on 20 Dec 2017 24 12.1



Record highest annual mean daily minimum temperature
New record
(°C)
Old
record
Years of
record
Annual
average
Badgerys Creek AWS 11.8 11.6 in 1998 24 10.9

Highest annual mean daily minimum temperature for at least 20 years
Observed
(°C)
Most recent
higher
Annual
average
Bankstown Airport AWS 12.9 13.0 in 1998 12.1
Camden Airport AWS 11.0 11.3 in 1998 10.2
Richmond RAAF 11.9 12.1 in 1998 11.1



* note: there are gaps in the historical record at this site, so it is possible a lower value has gone unreported




Summary statistics for 2020
Maximum temperatures
(°C)
Minimum temperatures
(°C)
Rainfall
(millimetres)
Mean
for
2020
Diff
from
average
Highest
for
2020
Mean
for
2020
Diff
from
average
Lowest
for
2020
Total
for
2020
Average
annual
total
Rank
of
2020
Fraction
of annual
average
Badgerys Creek AWS     47.6 4 Jan 11.8 +0.9 0.5 25 Aug
Bankstown Airport AWS 23.9 +0.5 47.0 4 Jan 12.9 +0.8 2.3 25 Aug 1113.8 871.3 high 128%
Camden Airport AWS 23.9 +0.1 46.2 4 Jan 11.0 +0.8 -1.2 27 Aug 1081.8 789.8 high 137%
Campbelltown (Mount Annan) 23.8 -0.4 45.5 4 Jan 11.1 +0.4 -0.3 5 Aug
Canterbury Racecourse AWS 23.2 +0.1 45.9 4 Jan 12.6 +0.2 1.7 25 Aug 1276.2 972.5 high 131%
Cooranbong (Lake Macquarie AWS) 23.6 -0.4 45.1 4 Jan 11.9 +0.5 -0.6 27 Aug 1496.4 1055.3 v high 142%
Gosford AWS 23.0   44.4 4 Jan 13.3   3.3 29 Aug
Holsworthy Aerodrome AWS 23.3   45.9 4 Jan 12.3   1.2 26 Aug 1166.0
Holsworthy Defence AWS 22.8   45.9 1 Feb 12.0   2.2 26 Aug 1340.4
Horsley Park Equestrian Centre AWS 23.5 -0.4 47.0 4 Jan 12.3 +0.2 1.6 25 Aug 1283.4 771.7 highest 166%
Katoomba (Farnells Rd) 17.9 +1.0 39.8 4 Jan 7.7 -0.4 -1.7 5 Aug 2015.7 1404.3 v high 144%
Mount Boyce AWS 17.4 +0.3 38.0 1 Feb 8.3 +0.2 -2.5 25 Aug 1585.6 984.7 highest 161%
Norah Head AWS 22.9 +0.5 41.5 29 Nov 15.5 +0.3 5.9 6 Aug
Parramatta North (Masons Drive) 23.6 +0.2 47.0 4 Jan 12.5 +0.3 1.7 25 Aug 1243.6 966.0 v high 129%
Penrith Lakes AWS 24.8 0.0 48.9 4 Jan 12.5 +0.1 0.7 6 Aug 1094.2 721.6 highest 152%
Richmond RAAF 24.3 0.0 47.4 4 Jan 11.9 +0.8 -0.9 6 Aug 935.4 728.1 high 128%
Springwood (Valley Heights) 22.3 -0.3 45.1 4 Jan 12.3 +0.2 1.5 6 Aug 1545.8 1082.0 v high 143%
Sydney (Observatory Hill) 23.5   41.2 23 Jan 14.7   6.2 25 Aug
Sydney Airport AMO 23.6 +1.2 43.7 23 Jan 14.8 +1.3 6.2 25 Aug 1222.6 1079.1 high 113%
Sydney Harbour (Wedding Cake West) 21.5 +0.2 40.4 23 Jan 15.9 +0.2 7.6 5 Aug
Sydney Olympic Park AWS (Archery Centre) 23.9   47.1 4 Jan 13.2   2.6 25 Aug 1264.6
Terrey Hills AWS 21.7 -0.3 44.5 4 Jan 13.4 +0.1 3.0 6 Aug

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.

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 Monday 4 January 2021. 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