Greater Sydney in 2021: wet and relatively cool

Greater Sydney in 2021 was wetter than usual, with totals around 10 to 60% above the average over recent decades. Very heavy rain in March resulted in significant flooding on the Hawkesbury River. Daytime and night-time temperatures were generally half to one degree below average.

Wetter than usual

  • Greater Sydney in 2021 was wetter than usual, with annual totals around 10 to 60% percent above the average over recent decades.
  • A few sites which have 25 years or less of data, had their highest total rainfall on record and a few other sites had their highest for at least 20 years.
  • It was very wet in March, with many sites having their wettest March on record.
  • The heaviest falls were from 19 to 23 March, resulting in significant flooding along the Hawkesbury River.
  • After a dry start to winter August was wetter than average, with two-day totals of 50 to 100 mm on the 24th and 25th from a coastal low.
  • It was very wet in November, with totals two to three times the monthly average from the passage of several low pressure troughs.

Relatively cool

  • Greater Sydney was relatively cool in 2021, with daytime and night-time temperatures generally around 0.5 to 1.0 °C below the average over recent decades.
  • Mangrove Mountain and Penrith Lakes, with 27 and 26 years of data respectively, had their lowest mean daily minimum temperature on record.
  • January was relatively cool overall, although Australia Day (26 January) was the hottest day of the year.
  • A complex low pressure system over New South Wales on 9 and 10 June brought very cold air. Snow was reported near Sydney in the Blue Mountains and at Oberon, and some sites had their coldest day on record on 10 June.
  • August and September had above average mean maximum temperatures.
  • It was the coolest November across Greater Sydney in over 20 years.

Sydney (Observatory Hill)

  • Total rainfall for Sydney (Observatory Hill) was 1290.2 mm, which is 106% of the average over all years at the former Observatory Hill site, or 139% of the average over recent decades.
  • The mean daily maximum temperature for Sydney (Observatory Hill) was 23.2 °C, which is 1.4 °C above the average over all years at the former Observatory Hill site, or 0.4 °C above the average over recent decades.
  • The warmest day was 37.1 °C on 26 January, and the coolest day was on 10 June when the temperature reached 10.3 °C.
  • The five consecutive days over 30 °C from 22 to 26 January was only the ninth such instance since records began, but the third year in a row that this has occurred.
  • The maximum of 10.3 °C on 10 June made it the second-coldest June day in the combined record at Observatory Hill, behind 9.7 °C on 13 June 1899.
  • The mean daily minimum temperature for Sydney (Observatory Hill) was 14.1 °C, which is 0.3 °C above the average over all years at the former Observatory Hill site, or 0.6 °C below the average over recent decades.
  • The coldest morning was 5.2 °C on 22 July, and the warmest morning was on 24 January when the minimum temperature was 22.2 °C.

Further information

Media
(03) 9669 4057

Extremes in 2021
Hottest day 41.6 °C at Sydney Airport AMO on 26 Jan
Warmest days on average 24.1 °C at Penrith Lakes AWS
Coolest days on average 16.4 °C at Mount Boyce AWS
Coldest day 1.3 °C at Mount Boyce AWS on 10 Jun
Coldest night -2.7 °C at Richmond RAAF on 30 Jul
Coolest nights on average 7.6 °C at Mount Boyce AWS
Warmest nights on average 15.4 °C at Sydney Harbour (Wedding Cake West)
Warmest night 23.2 °C at Cooranbong (Lake Macquarie AWS) on 27 Jan
Warmest on average overall 18.7 °C at Norah Head AWS
Coolest on average overall 12.0 °C at Mount Boyce AWS
Wettest overall 1838.8 mm at Katoomba (Farnells Rd)
Wettest day 205.3 mm at Mt Irvine (Booralee) on 22 Mar
Strongest wind gust 111 km/h at Wattamolla AWS on 19 Jun

Record highest annual total rainfall

New record
(mm)
Old
record
Years of
record
Annual
average
Penrith Lakes AWS 1180.8 1094.2 in 2020 25 740.0
Richmond RAAF 1053.0 1051.2 in 2007 25 741.1
Badgerys Creek AWS 1064.0 1041.8 in 2007 24 675.0
Blackheath (Wombat Street) 1786.0 1762.0 in 2020 20 1130.0

Highest annual total rainfall for at least 20 years

Observed
(mm)
Most recent
higher
Annual
average
Campbelltown (Kentlyn (Georges River Roa 1134.0 1283.2 in 1978* 764.9
Richmond - UWS Hawkesbury 1046.6 1426.6 in 1990* 798.9

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




Record lowest daily maximum temperature

New record
(°C)
Old
record
Years of
record
Annual
average
Bankstown Airport AWS 9.6 on 10 Jun = 9.6 on 20 Jul 1983 54 23.4
Camden Airport AWS 8.4 on 10 Jun 9.6 on 20 Jul 1983 48 23.8
Mount Boyce AWS 1.3 on 10 Jun 1.8 on 31 Jul 1994 31 17.1
Richmond RAAF 8.3 on 10 Jun 9.5 on 13 Jul 2011 29 24.3
Badgerys Creek AWS 8.5 on 10 Jun 10.5 on 13 Jul 1997 27 24.0
Canterbury Racecourse AWS 10.2 on 10 Jun 11.3 on 19 Aug 1996 27 23.1
Penrith Lakes AWS 8.3 on 10 Jun 11.2 on 26 Jul 2009 27 24.8
Horsley Park Equestrian Centre AWS 8.9 on 10 Jun 10.9 on 13 Jul 2011 25 23.8



Record lowest annual mean daily minimum temperature

New record
(°C)
Old
record
Years of
record
Annual
average
Mangrove Mountain AWS 10.8 10.9 in 2012 27 11.6
Penrith Lakes AWS 11.6 = 11.6 in 1996 26 12.4



Lowest annual mean temperature for at least 20 years

Observed
(°C)
Most recent
lower
Annual
average
Camden Airport AWS 16.5 16.1 in 1992* 17.0

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




Summary statistics for 2021

Maximum temperatures
(°C)
Minimum temperatures
(°C)
Rainfall
(millimetres)
Mean
for
2021
Diff
from
average
Highest
for
2021
Mean
for
2021
Diff
from
average
Lowest
for
2021
Total
for
2021
Average
annual
total
Rank
of
2021
Fraction
of annual
average
Badgerys Creek AWS 23.3 -0.7 40.6 26 Jan 10.4 -0.5 -1.3 30 Jul 1064.0 675.0 highest 158%
Bankstown Airport AWS 23.3 -0.1 40.5 26 Jan 12.0 -0.1 0.6 30 Jul 944.8 868.0 average 109%
Camden Airport AWS 23.1 -0.7 39.9 24 Jan 9.9 -0.4 -2.1 22 Jul 1064.0 796.6 high 134%
Campbelltown (Mount Annan)     40.0 24 Jan 10.2 -0.5 -1.1 30 Jul 1027.2 719.9 v high 143%
Canterbury Racecourse AWS 22.5 -0.6 39.5 26 Jan 11.8 -0.5 1.2 30 Jul



Cooranbong (Lake Macquarie AWS) 23.1 -0.8 37.8 26 Jan 10.9 -0.5 -1.8 30 Jul 1343.6 1079.3 high 124%
Gosford AWS 22.4   38.7 26 Jan 12.6   0.8 30 Jul 1428.6


Holsworthy Aerodrome AWS 22.6   39.6 26 Jan 11.4   0.3 30 Jul 946.0


Holsworthy Defence AWS 22.2   41.2 26 Jan 11.1   0.7 10 Jun 1180.0


Horsley Park Equestrian Centre AWS 22.9 -0.9 39.1 26 Jan 11.5 -0.6 -0.2 22 Jul 977.0 780.3 high 125%
Mangrove Mountain AWS 22.0 0.0 37.3 26 Jan 10.8 -0.8 -0.5 22 Jul 1546.6 1127.9 high 137%
Mount Boyce AWS 16.4 -0.7 33.2 24 Jan 7.6 -0.5 -1.6 6 Jul 1557.0 1005.9 v high 155%
Norah Head AWS 22.6 +0.2 36.0 26 Jan 14.9 -0.3 6.0 11 Jun 1392.2 1163.9 high 120%
Parramatta North (Masons Drive) 23.0 -0.4 40.0 26 Jan     2.3 30 Jul 1092.0 968.3 high 113%
Penrith Lakes AWS 24.1 -0.7 40.7 26 Jan 11.6 -0.8 -0.6 22 Jul 1180.8 740.0 highest 160%
Richmond RAAF 23.5 -0.8 39.8 26 Jan 10.6 -0.5 -2.7 30 Jul 1053.0 741.1 highest 142%
Sydney (Observatory Hill) 23.2   37.1 26 Jan 14.1   5.2 22 Jul 1290.2


Sydney Airport AMO 22.8 +0.4 41.6 26 Jan 14.2 +0.6 4.6 11 Jun 1196.6 1080.4 high 111%
Sydney Harbour (Wedding Cake West) 20.9 -0.4 34.4 19 Dec 15.4 -0.3 7.2 11 Jun



Sydney Olympic Park AWS (Archery Centre) 23.2 -0.9 41.0 26 Jan 12.5 -0.5 1.8 30 Jul 1026.8


Terrey Hills AWS 21.2 -0.7 37.5 26 Jan 12.7 -0.6 2.9 30 Jul 1372.0 1101.7 high 125%

Notes

The Annual climate summary 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 5 pm on Monday 7 February 2022. 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