Greater Sydney in autumn 2020: near average rainfall, below average temperature

Autumn 2020 was fairly typical with rainfall being close to average throughout. Mean maximum temperatures were a little cooler than usual inland, but near average along the coast. Minimum temperatures were slightly below average in most areas.

Near average rainfall

  • Greater Sydney recorded near average rainfall for autumn, ranging from 72% of average at Springwood (Valley Heights) to 117% of average at Horsley Park Equestrian Centre
  • Autumn began with wetter than average conditions in March, followed by below average rainfall in April and near to above average rainfall in May
  • The wettest period for autumn was from 4 to 6 March, as an inland trough drew in tropical moisture from Ex-Tropical Cyclone Esther; most sites recorded three day totals of 50 mm to 100 mm
  • Sydney (Observatory Hill) had 46 rain days in autumn, compared to the average of 39 days
  • Sydney Airport recorded on average 6.1 hours of bright sunshine per day in autumn, below the average of 6.7 hours

Cooler than average days and nights

  • Mean maximum temperatures for autumn were generally up to 1 °C cooler than average inland and close to average along the coastal fringe, ranging from 1.0 °C below average at Campbelltown (Mount Annan) to 1.0 °C above average at Sydney (Observatory Hill)
  • There were 30 days where the maximum temperature reached 25 °C or higher at Sydney (Observatory Hill), which is above the average of 21 days, and 3 days in March where the temperature exceeded 30 °C
  • Mean minimum temperatures were up to 1 °C cooler than average, with the exception of Sydney (Observatory Hill) and Sydney Airport, which were 0.3 °C and 0.6 °C above average respectively
  • Katoomba had its lowest autumn mean daily minimum temperature since 1917

Sydney (Observatory Hill)

  • Total rainfall was 306.8 mm, which is 82% of the long-term average of 375.5 mm
  • The mean daily maximum temperature was 23.3 °C, which is 1.0 °C above the long-term average of 22.3 °C
  • The warmest day was 37.6 °C on 2 March, and the coolest day was on 15 May when the temperature reached 15.6 °C
  • The mean daily minimum temperature was 15.0 °C, which is 0.3 °C above the long-term average of 14.7 °C
  • The coldest morning was 7.8 °C on 11 May, and the warmest morning was on 6 March when the minimum temperature was 20.9 °C

Further information

Media
(03) 9669 4057

Extremes in autumn 2020
Hottest day 39.6 °C at Sydney Airport AMO on 2 Mar
Warmest days on average 24.0 °C at Penrith Lakes AWS
Coolest days on average 16.2 °C at Mount Boyce AWS
Coldest day 5.8 °C at Mount Boyce AWS on 1 May
Coldest night -0.4 °C at Katoomba (Farnells Rd) on 11 May
-0.4 °C at Katoomba (Farnells Rd) on 22 May
Coolest nights on average 7.6 °C at Katoomba (Farnells Rd)
Warmest nights on average 16.3 °C at Sydney Harbour (Wedding Cake West)
Warmest night 21.6 °C at Terrey Hills AWS on 2 Mar
21.6 °C at Gosford AWS on 6 Mar
Warmest on average overall 19.4 °C at Norah Head AWS
Coolest on average overall 12.2 °C at Mount Boyce AWS
Wettest overall 404.0 mm at Avalon Beach (Avalon (Palmgrove Rd))
Wettest day 73.5 mm at Katoomba (Farnells Rd) on 26 Mar
Strongest wind gust 109 km/h at Wattamolla AWS on 24 May

Lowest autumn mean daily minimum temperature for at least 20 years
Observed
(°C)
Most recent
lower
Average for
autumn
Katoomba (Farnells Rd) 7.6 7.1 in 1917* 8.8

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




Summary statistics for autumn 2020
Maximum temperatures
(°C)
Minimum temperatures
(°C)
Rainfall
(millimetres)
Mean for
autumn
2020
Diff
from
average
Highest for
autumn
2020
Mean for
autumn
2020
Diff
from
average
Lowest for
autumn
2020
Total for
autumn
2020
Average
for
autumn
Rank of
autumn
2020
Fraction of
autumn
average
Badgerys Creek AWS 23.0 -1.0 36.4 2 Mar 11.5 0.0 2.6 12 May 195.2 171.3 average 114%
Bankstown Airport AWS 23.5 -0.1 38.0 2 Mar 12.7 -0.1 4.9 12 May 219.4 246.5 average 89%
Camden Airport AWS 23.3 -0.5 36.8 2 Mar 10.4 -0.6 0.8 11 May 180.6 208.8 average 86%
Campbelltown (Mount Annan) 23.1 -1.1 36.9 2 Mar 10.9 -0.4 2.3 12 May 176.6 176.7 average 100%
Canterbury Racecourse AWS 23.1 -0.3 37.3 2 Mar 12.2 -0.7 4.8 12 May 260.4 259.5 average 100%
Cooranbong (Lake Macquarie AWS) 23.3 -0.9 37.0 2 Mar 11.8 -0.2 2.5 12 May 308.2 268.9 average 115%
Gosford AWS 22.9   36.7 2 Mar 13.2   5.3 12 May 270.4
Holsworthy Aerodrome AWS 22.8   37.5 2 Mar 12.1   3.5 12 May 213.8
Holsworthy Defence AWS 22.1   37.5 2 Mar 12.0   4.6 12 May 224.6
Horsley Park Equestrian Centre AWS 22.8 -1.0 37.1 2 Mar 12.4 -0.3 3.6 12 May 230.8 197.0 average 117%
Katoomba (Farnells Rd) 16.9 +0.1 30.7 2 Mar 7.6 -1.2 -0.4 11 May 362.0 389.0 average 93%
Mangrove Mountain AWS 21.4 -0.5 37.2 2 Mar 11.6 -0.5 1.2 11 May 293.8 300.8 average 98%
Mount Boyce AWS 16.2 -1.0 29.8 2 Mar 8.3 -0.4 -0.1 22 May 260.8 234.5 average 111%
Norah Head AWS 23.2 +0.3 36.4 2 Mar 15.7 -0.3 9.3 11 May 329.4 370.5 average 89%
Parramatta North (Masons Drive) 23.1 -0.6 37.7 2 Mar 12.4 -0.5 3.0 11 May 220.6 267.5 average 82%
Penrith Lakes AWS 24.0 -0.5 39.5 2 Mar 12.3 -0.8 2.5 11 May 179.8 161.8 average 111%
Richmond RAAF 23.5 -0.6 38.7 2 Mar 11.5 -0.2 1.1 11 May 151.0 177.8 average 85%
Springwood (Valley Heights) 21.4 -1.0 37.0 2 Mar 12.4 -0.1 6.0 22 May 206.0 285.7 average 72%
Sydney (Observatory Hill) 23.3 +1.0 37.6 2 Mar 15.0 +0.3 7.8 11 May 306.8 375.5 average 82%
Sydney Airport AMO 23.5 +0.7 39.6 2 Mar 14.9 +0.6 7.9 11 May 270.2 319.3 average 85%
Sydney Harbour (Wedding Cake West) 22.1 0.0 34.8 20 Mar 16.3 -0.2 10.0 11 May
Sydney Olympic Park AWS (Archery Centre) 23.5   37.9 2 Mar 13.2   5.7 11 May 228.4
Terrey Hills AWS 21.6 -0.7 36.3 2 Mar 13.6 -0.3 6.4 12 May

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 9 am on Monday 1 June 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