Australian Capital Territory in autumn 2020: wet with cool days

It was a wet autumn in the ACT, with rainfall generally above average. Daytime temperatures were well below average, with overnight minimum temperatures near average.

A wet autumn in the ACT

  • Rainfall in the ACT was above average at all locations
  • March and April were both significantly wetter than average, with the season's most significant rain event occurring in early March
  • May rainfall was generally close to average

Cool days and near-average nights

  • Daytime maximum temperatures were 1 to 2 °C below average at all ACT locations
  • All three autumn months had cooler days than average
  • Tuggeranong had its lowest autumn mean daily maximum temperature on record since records began in 1996
  • Overnight minimum temperatures were near average

Canberra Airport

  • Total rainfall for Canberra Airport was 198.2 mm, which is 143% of the long-term average of 138.5 mm. This was the wettest autumn since 2012.
  • The mean daily maximum temperature for Canberra Airport was 19.1 °C, which is 1.1 °C below the long-term average of 20.2 °C and the lowest since 1984. The warmest day was 31.1 °C on 2 March, and the coolest day was on 1 May when the temperature reached 9.4 °C
  • The mean daily minimum temperature for Canberra Airport was 7.2 °C, which is 0.4 °C above the long-term average of 6.8 °C. The coldest morning was -3.0 °C on 11 May, and the warmest morning was on 6 March when the minimum temperature was 17.3 °C

Cold outbreak at the end of April

  • A major early-season cold outbreak affected the ACT at the end of April and start of May, with heavy snowfalls in the Brindabellas
  • Canberra Airport failed to reach 10 °C on 30 April, the earliest day below 10 °C in autumn since 1952
  • A 48-hour period of steady rain occurred between 4 and 6 March, with most sites receiving 70 to 90 mm over this period

Further information

Media
(03) 9669 4057

Extremes in autumn 2020
Hottest day 31.1 °C at Canberra Airport on 2 Mar
Warmest days on average 19.2 °C at Tuggeranong (Isabella Plains) AWS
Coolest days on average 10.2 °C at Mount Ginini AWS
Coldest day -1.8 °C at Mount Ginini AWS on 1 May
Coldest night -5.0 °C at Mount Ginini AWS on 10 May
Coolest nights on average 3.2 °C at Mount Ginini AWS
Warmest nights on average 7.2 °C at Canberra Airport
7.2 °C at Tuggeranong (Isabella Plains) AWS
Warmest night 17.4 °C at Tuggeranong (Isabella Plains) AWS on 6 Mar
Warmest on average overall 13.2 °C at Tuggeranong (Isabella Plains) AWS
Coolest on average overall 6.7 °C at Mount Ginini AWS
Wettest overall 364.0 mm at Mount Ginini AWS
Driest overall 198.2 mm at Canberra Airport
Wettest day 58.4 mm at Mount Ginini AWS on 5 Mar
Strongest wind gust 83 km/h at Mount Ginini AWS on 11 Apr

Record lowest autumn mean daily maximum temperature
New record
(°C)
Old
record
Years of
record
Average for
autumn
Tuggeranong (Isabella Plains) AWS 19.2 19.3 in 2012 23 21.0



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
Canberra Airport 19.1 -1.1 31.1 2 Mar 7.2 +0.4 -3.0 11 May 198.2 138.5 high 143%
Mount Ginini AWS 10.2 -1.8 21.4 19 Mar 3.2 -1.0 -5.0 10 May 364.0 210.3 high 173%
Tuggeranong (Isabella Plains) AWS 19.2 -1.8 30.2 1 Mar 7.2 +0.2 -3.2 11 May 203.2 114.6 high 177%
Note: Observations for “Canberra Airport” are taken from the current site (Bureau number 070351), which opened in late 2008.
Comparisons are made against data from the previous site Canberra Airport Comparison (070014), which ran from 1939 to 2010,
combined with the current site from March 2010 onwards.

Notes

The Seasonal climate summary, generally published on the first working day of each month, lists the main features of the weather in Australian Capital Territory 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 Australian Capital Territory “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 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