Tuesday 03 January 2006

Sydney Climate Summary - NSW Regional Office 

Second warmest December on record in Sydney

December 2005

Temperatures:   Sydney recorded its 2nd warmest December since records commenced in 1859.  The mean temperature for the month (average of daily maximum and minimum temperatures) was 23.8 °C which is 2.3°C above the historic December average*.   The warmest December was in 1990 with an monthly mean temperature of 24.4°C.  Days were particularly warm with an average maximum temperature of 28.6°C or 3.4°C above the historic average and the same as 1990.   The number of hot days (30°C or more) equalled the record of 11 days set in 1957.  Although no minimum temperature records were broken there were 9 nights when the temperature did not fall below 20°C, more than twice the historic average of 4.  Temperatures at Observatory Hill ranged from 39°C on the 7th to an overnight low of 15.3°C on the 20th.   Metropolitan temperatures ranged from 40.1°C at Sydney Olympic Park on the 7th and at Penrith on 31st to an overnight low of  8.5°C at Badgerys Creek on the 20th.

Sunshine and humidity:  December was Sydney's sunniest month on record. The average daily sunshine was 10.4 hours compared to the historic average of 7.9 hours. The previous sunniest month was September 1980 with an average of 10.1 hours per day (records since 1931).  Afternoon humidity levels in Sydney were the lowest on record for December, averaging 47% at 3pm (historic average 60%). The previous lowest was 49% in December 1976 (records since 1955).

Rainfall:  Sydney's total rainfall of 25.2mm was well below the historic December average of 78.1mm. It was the driest December since 1986 (when 8.6mm was recorded). The rain fell on 5 days which is well below the average of 11 days and the lowest for December since 3 rain days in 1974. Although 4 thunderstorms were reported over the greater Sydney area during the month, only 2 thunderstorms were recorded at Observatory Hill (historic average 4 storms). Rainfall was light and patchy across the greater Sydney area, monthly totals ranging from 40mm at Glenorie in Sydney's north-west to 15mm at Bankstown. The Warragamba Dam catchment area received only light falls during December.  The lower catchment recorded monthly totals of 40-60mm while the upper catchment received only 10-20mm. Recent rainfall over Sydney's catchments can be found on the Sydney Catchment Authority web site:    http://www.sca.nsw.gov.au/dams/rainfall.html

Further information:
Mike De Salis, Climate and Consultancy Section, tel: (02) 9296 1555, e-mail: reqnsw@bom.gov.au

Climate summary for Sydney,  December 2005

December
2005Average2004
Average maximum
temperature (°C)
28.625.2*25.6
Average minimum
temperature (°C)
18.917.8*18.1
Mean
temperature (°C)
23.821.5*21.8
Rain
(mm)
25.278.1#75.8
Number of
rain days
51113
Average daily
sunshine (hours)
10.47.97.9

** Long-term temperature averages at Sydney (Observatory Hill) are from 1947 to present, due to a change at the site in that year.
# Median December rainfall is 57mm.
Climate averages for Sydney are available, here

 

December 2005 Daily Extremes
ElementDecember 2005DateExtremeDate
Highest daily maximum (°C)39.007/12/200542.220/12/1957
Lowest daily minimum (°C)15.320/12/20059.103/12/1924
Wettest 24 hours (mm)15.803/12/2005126.009/12/1970
Maximum Wind Gust (km/h) WNW @ 74*02/12/2005W @ 121**10/12/1938
* recorded at Fort Denison  **recorded at Observatory Hill.

Use Weather by Fax for updates and other products: 
NSW Directory 1800 061 439
Sydney Monthly Weather Summary 1902 935 225 
NSW Monthly Weather Summary 1902 935 224 
Australian 3-month Climate Outlook 1902 935 251 
NSW Daily Rainfall Bulletin 1902 935 223

Bureau's web site:   www.bom.gov.au