Melbourne Metropolitan Area in December 2010: A humid start to summer

  • Above average rainfall
  • Very humid conditions in early December
  • Warm nights and close to normal days

Rainfall

The Central district experienced another above average month for rainfall. Coldstream, Cranbourne Botanic Gardens and Scoresby Research Institute recorded rainfall totals more than double that usually received in December.

The wettest location this month was Ferny Creek (Dunns Hill), which recorded 166.0 mm, in line with its neighbours to the northeast of the region, including Coldstream and Scoresby Research Institute, where monthly totals of more than 145 mm were also reported. In contrast, some locations only received rainfall totals close to their long-term average, including Avalon Airport and Laverton RAAF, with only 26.0 mm and 55.4 mm of rainfall for the month respectively.

Heavy rainfall in the eastern half of the Central district recorded on the 20th delivered 50.0 mm to Scoresby Research Institute and 22.2 mm reported at the Melbourne Regional Office. A strong system passed across the state in the 24 hours to 9am on the 9th bringing the highest daily total for the month to several sites in the Melbourne Metropolitan region including the Melbourne Regional Office (28.8 mm), Essendon Airport (23.4 mm) and Moorabbin Airport (32.6 mm).

Maximum temperature

Maximum temperatures in the Central district in December 2010 were generally very close to the long-term average. Stations to the north of Melbourne reported average daytime temperatures slightly below the climatological average. Viewbank experienced a slightly cool start to summer with December days around 0.8 C cooler than usual.

Melbourne Regional Office, on the other hand, reported warmer than normal days, the warmest of which was the 31st of December, a scorching 41.1 C for New Years Eve celebrations. Across the Melbourne region, and much of Victoria, temperatures on the final day of 2010 soared well above 40 C. Avalon Airport recorded the hottest day for the region on the 31st, a sweltering 42.8 C.

Chilly days occurred mid-month with a cold outbreak bringing snow to parts of Victoria. Across the Melbourne region, unseasonably cool conditions were experienced, with daily maximum temperatures between the 18th and 21st restrained to below 20 C.  

Minimum temperature

Night-time temperatures were generally above average in the Melbourne Metropolitan area for December. The warmest nights were experienced at the Melbourne Regional Office, averaging 14.5 C, more than 1.6 C above the long-term average for this site.

Systems of tropical origin passed through the Victorian region early in the month and brought very humid conditions to Melbourne. Dewpoint temperatures reached 20.0 C on several occasions in the first weeks of the month, a very rare occurrence for Melbourne in December. The warmest night was the 8th, with a balmy minimum of 22.6 C recorded at the Melbourne Regional Office.

The 22nd and 28th were the coolest nights in the Melbourne Metropolitan area, with temperatures dropping to just 4.3 C at Coldstream on the 28th and below 6 C in surrounding areas. Ferny Creek (Dunns Hill) experienced the coolest nights for the region, averaging 10.2 C, equal to the long-term average at this site.

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Extremes in December 2010
Hottest day 42.8 C at Avalon Airport on the 31st
Warmest days on average 24.9 C at Bundoora (Latrobe University)
Coolest days on average 19.6 C at Ferny Creek (Dunns Hill)
Coldest day 10.9 C at Ferny Creek (Dunns Hill) on the 21st
Coldest night 4.3 C at Coldstream on the 28th
Coolest nights on average 10.2 C at Ferny Creek (Dunns Hill)
Warmest nights on average 14.5 C at Melbourne Regional Office
Warmest night 22.6 C at Melbourne Regional Office on the 8th
Warmest on average overall 19.6 C at Melbourne Regional Office
Coolest on average overall 14.9 C at Ferny Creek (Dunns Hill)
Wettest overall 166.0 mm at Ferny Creek (Dunns Hill)
Driest overall 26.0 mm at Avalon Airport
Wettest day 50.0 mm at Scoresby Research Institute on the 20th
Highest wind gust 94 km/h at Avalon Airport on the 3rd

Summary statistics for December 2010
Maximum temperatures
for December
(C)
Minimum temperatures
for December
(C)
Rainfall
for December
(millimetres)
Mean for
December
2010
Diff
from
average
Highest for
December
2010
Mean for
December
2010
Diff
from
average
Lowest for
December
2010
Total for
December
2010
Average
for
December
Rank of
December
2010
Fraction of
December
average
East Central (district 86)
Bundoora (Latrobe University) 24.9 +0.2 40.8 31st 12.5 +0.2 5.5 28th 76.0 64.2 average 118%
Cerberus 22.4 +0.2 38.7 31st 12.2 +0.4 6.0 22nd 78.8 53.1 high 148%
Coldstream 24.5 -0.4 39.2 31st 11.1 +1.7 4.3 28th 145.6 53.6 v high 272%
Cranbourne Botanic Gardens 22.9 -0.4 38.9 31st 11.7 0.0 6.5 24th 133.4 64.9 v high 206%
Essendon Airport 24.4 +0.1 40.7 31st 12.5 +0.8 6.2 28th 63.6 51.5 high 123%
Ferny Creek (Dunns Hill) 19.6 -0.3 34.2 31st 10.2 0.0 5.3 28th 166.0 88.8 high 187%
Melbourne Airport 24.1 -0.3 40.4 31st 11.9 -0.1 6.0 28th 86.6 49.3 high 176%
Melbourne Regional Office 24.8 +0.6 41.1 31st 14.5 +1.6 9.0 28th 85.2 59.3 high 144%
Moorabbin Airport 23.5 -0.3 40.2 31st 13.1 +0.6 7.8 28th 111.2 59.6 v high 187%
Scoresby Research Institute 23.9 0.0 39.6 31st 12.1 +0.3 5.1 28th 153.2 76.6 v high 200%
Viewbank (ARPANSA) 24.6 -0.8 40.5 31st 12.5 +0.1 4.9 28th 109.2 69.1 high 158%
West Central (district 87)
Avalon Airport 24.0 0.0 42.8 31st 11.5 -0.1 5.2 22nd 26.0 29.6 average 88%
Laverton RAAF 23.6 -0.1 41.9 31st 12.1 +0.2 6.6 22nd 55.4 45.8 average 121%

Notes

A Monthly Climate Summary is prepared to list the main features of the weather in Melbourne Metropolitan Area and Environs using the most timely and accurate information available on the date of publication; it will generally not be updated. Later information, including data that has had greater opportunity for quality control, will be presented in the Monthly Weather Review, usually published in the fourth week of the month.

This statement has been prepared based on information available at 10 am on Wednesday 5 January 2011. Some checks have been made on the data, but it is possible that results will change as new information becomes available.

Averages 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.

Further information

Media
(03) 9669 4057
Enquiries