Greater Melbourne in autumn 2020: much wetter than average, cool days

Autumn rainfall totals were very much above average in most suburbs. Days were cooler than average across Greater Melbourne, while night-time temperatures were generally close to average.

Much wetter than average

  • Autumn rainfall across Greater Melbourne was very much above average at most reporting sites, ranging from 138% above average at Ferny Creek, to 221% above average at Melbourne Airport
  • In March and April, rainfall was above average, while in May it was close to average across Greater Melbourne
  • Some sites had their highest autumn daily rainfall on record on 5 March, when a low pressure trough which extended to the tropics, brought moisture from ex-tropical cyclone Esther, and widespread rainfall to Greater Melbourne
  • The highest daily rainfall total this season, 96.2 mm, was recorded at Willowmavin, also on 5 March
  • Some sites had either their highest total autumn rainfall on record, or highest total autumn rainfall since at least 1995
  • Ferny Creek recorded the highest autumn rainfall total in Greater Melbourne of 447.0 mm

Cool days

  • Autumn daytime temperatures were cooler than average in all Melbourne suburbs
  • Mean maximum temperature ranged from 0.8 °C below average at Cerberus to 1.9 °C below average at Viewbank
  • Viewbank had its lowest autumn mean daily maximum temperature on record, while Melbourne Airport and Essendon Airport had their lowest autumn mean daily maximum temperature for at least 20 years
  • The lowest daytime temperature this autumn was 6.4 °C at Ferny Creek on 1 May, in the wake of a vigorous cold front which brought winter-like conditions to Greater Melbourne
  • Night-time temperatures were generally close to average

Melbourne (Olympic Park)

  • Total rainfall for Melbourne (Olympic Park) was 276.2 mm
  • The mean daily maximum temperature for Melbourne (Olympic Park) was 19.5 °C
  • The warmest day was 32.1 °C on 1 March, and the coolest day was on 1 May when the temperature reached 13.0 °C, the coldest 1 May day in Melbourne city since 1962
  • The mean daily minimum temperature for Melbourne (Olympic Park) was 11.4 °C
  • The coldest morning was 4.5 °C on 15 May (the coldest May morning for this site since 2016), and the warmest morning was on 13 March when the minimum temperature was 19.1 °C

Heavy rain and flash flooding

  • Heavy rainfall on 5 March, brought by the remnants of the ex-tropical cyclone Esther, caused flash flooding and building damage; there were many delays on tram and train lanes due to signal faults, flooded tracks and train stations

Further information

Media
(03) 9669 4057

Extremes in autumn 2020
Hottest day 33.6 °C at Essendon Airport on 1 Mar
Warmest days on average 19.5 °C at Coldstream
19.5 °C at Melbourne (Olympic Park)
19.5 °C at Moorabbin Airport
19.5 °C at Viewbank
Coolest days on average 15.4 °C at Ferny Creek
Coldest day 6.4 °C at Ferny Creek on 1 May
Coldest night -1.2 °C at Coldstream on 15 May
Coolest nights on average 7.5 °C at Coldstream
Warmest nights on average 11.4 °C at Melbourne (Olympic Park)
Warmest night 19.8 °C at Laverton RAAF on 13 Mar
Warmest on average overall 15.5 °C at Melbourne (Olympic Park)
Coolest on average overall 11.9 °C at Wallan (Kilmore Gap)
Wettest overall 447.0 mm at Ferny Creek
Wettest day 96.2 mm at Willowmavin (Avalon Station) on 5 Mar
Strongest wind gust 104 km/h at South Channel Island on 11 Apr

Record highest autumn daily rainfall
New record
(mm)
Old
record
Years of
record
Romsey 81.6 on 5 Mar 70.4 on 15 May 1974 49
Upper Plenty 89.0 on 5 Mar 80.6 on 24 Apr 2001 35
Springvale (Sandown) 60.0 on 5 Mar 56.0 on 6 Apr 1989 32
Cranbourne Botanic Gardens 59.0 on 5 Mar 54.4 on 22 Apr 2001 31
Newham (Cobaw) 75.0 on 5 Mar 64.8 on 10 Apr 2017 26



Record highest autumn total rainfall
New record
(mm)
Old
record
Years of
record
Average for
autumn
Wallan 299.2 293.2 in 1989 39 146.9
Upper Plenty 371.6 281.0 in 1995 34 166.8
Wallan (Kilmore Gap) 332.4 314.4 in 2001 26 160.9
Coldstream 336.0 262.4 in 2011 24 180.0
Newham (Cobaw) 310.4 217.8 in 1995 22 153.3
Viewbank 320.2 260.8 in 2011 21 155.9

Highest autumn total rainfall for at least 20 years
Observed
(mm)
Most recent
higher
Average for
autumn
Oakleigh (Metropolitan Golf Club) 332.0 379.8 in 1970* 184.6
Melbourne Airport 269.8 322.1 in 1974 122.0
Romsey 335.0 359.1 in 1974* 154.8
Scoresby Research Institute 372.6 426.0 in 1970* 211.3
Lancefield 341.1 343.8 in 1974* 162.2
Eltham 296.2 298.6 in 1978* 182.0
Melbourne Botanical Gardens 306.0 328.1 in 1974* 159.0
Essendon Airport 252.8 317.2 in 1974* 142.8
Woodend 298.4 335.6 in 1989* 178.9
Springvale Necropolis 318.5 329.0 in 1995* 206.3
Springvale (Sandown) 338.6 346.4 in 1995* 174.0
Kinglake West 415.0 518.0 in 1995* 237.3

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




Record lowest autumn mean daily maximum temperature
New record
(°C)
Old
record
Years of
record
Average for
autumn
Viewbank 19.5 19.6 in 2011 20 21.4

Lowest autumn mean daily maximum temperature for at least 20 years
Observed
(°C)
Most recent
lower
Average for
autumn
Melbourne Airport 19.1 18.8 in 1996 20.5
Essendon Airport 19.2 =19.2 in 1970* 20.3

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




Record lowest autumn mean temperature
New record
(°C)
Old
record
Years of
record
Average for
autumn
Viewbank 14.7 14.8 in 2011 20 15.9

Lowest autumn mean temperature for at least 20 years
Observed
(°C)
Most recent
lower
Average for
autumn
Melbourne Airport 14.4 14.3 in 1996 15.5



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
Cerberus 19.1 -0.8 32.0 1 Mar 10.5 +0.1 1.3 18 May 256.4 176.5 high 145%
Coldstream 19.5 -1.4 31.7 19 Mar 7.5 0.0 -1.2 15 May 336.0 180.0 highest 187%
Essendon Airport 19.2 -1.1 33.6 1 Mar 10.5 +0.3 2.6 17 May 252.8 142.8 v high 177%
Ferny Creek 15.4   27.6 19 Mar 9.0   2.2 10 May 447.0 324.6 v high 138%
Laverton RAAF 19.3 -1.0 33.0 1 Mar 10.4 +0.3 2.3 16 May 190.6 125.6 high 152%
Melbourne (Olympic Park) 19.5   32.1 1 Mar 11.4   4.5 15 May 276.2
Melbourne Airport 19.1 -1.4 32.5 1 Mar 9.8 -0.6 1.3 26 May 269.8 122.0 v high 221%
Moorabbin Airport 19.5 -0.9 32.2 1 Mar 10.9 +0.1 2.2 26 May 280.6 175.0 v high 160%
Scoresby Research Institute 19.2 -1.0 31.3 1 Mar 9.9 -0.4 0.3 26 May 372.6 211.3 v high 176%
Viewbank 19.5 -1.9 32.3 1 Mar 9.8 -0.5 1.7 15 May 320.2 155.9 highest 205%
Wallan (Kilmore Gap) 15.5 -1.8 29.2 1 Mar 8.4 -0.6 2.9 10 May 332.4 160.9 highest 207%

Notes

The Seasonal climate summary, generally published on the first working day of each month, lists the main features of the weather in Greater Melbourne 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 Melbourne “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 10 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