Sydney Climate Summary - NSW Regional Office

Cloudy and humid with warm nights in Sydney during January

January 2006

Temperatures:   Warm nights prevailed in Sydney during January with an average monthly minimum temperature of 20.6°C or 1.6°C above the historic monthly average*.  This is the second highest average minimum temperature on record for January and the highest since 1991 (when 21.0°C).  Observatory Hill recorded 13 nights when the temperature did not fall below 21°C, more than 3 times the historic average of 4 nights. The average monthly maximum temperature was also above the historic average by 1°C.   The average monthly temperature (average of maximum and minimum temperatures) was 23.7 °C which is 1.2°C above the historic January average* (8th warmest on record).   The warmest January was in 1991 with an average temperature of 25.0°C.  The highest temperature recorded at Observatory Hill during the month was a hot 44.2°C on New Year's Day which is second only to the all time high of 45.3°C recorded in January 1939 (records since 1859). The lowest temperature was a mild 18.3°C on the 5th.   Metropolitan temperatures ranged from 45.2°C at Sydney Airport on the 1st (the highest on record for this site) to an overnight low of 15°C at Camden on the 8th.

Sunshine and humidity:  Cloudy and very humid conditions prevailed throughout January with sunshine hours well below the historic average.  Average daily sunshine recorded at Sydney Airport was only 6.2 hours per day (historic average 7.5 hours) and the 4th lowest on record. This contrasts significantly with last month when December was the sunniest month on record in Sydney (average 10.4 hours/day).  The cloudy conditions combined with prevailing NE-SE winds caused high humidity levels during January, also contrasting sharply with last months record low humidity.  High humidity was particularly noticeable during the early morning with an average of 79% at 9am, the highest ever recorded at this time during January (historic average at 9am is 70%, records since 1955). Oppressive conditions prevailed on the 16th when the humidity hovered around 85-95% all day and the temperature reached 26°C.

Rainfall:  Sydney's total rainfall of 121.4mm was slightly above the historic January average of 103mm. Rain was recorded on 17 of the first 20 days of the month.  There was a total of 19 rain days during January, well above the historic average of 12 days and the highest for January since 1989 (when 20 days).   Sydney metropolitan monthly rain totals were varied, ranging from 180mm at Castle Cove and 130mm at Merrylands to 61mm at Marrackville.   Two thunderstorms were recorded in Sydney during the month, the most severe on the 16th when 27mm was recorded in 2 hours.  Storm activity caused variable rainfall totals over the Warragamba Dam catchment area during January with most totals ranging from 100 to 200mm.   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 1542, e-mail: reqnsw@bom.gov.au

Climate summary for Sydney,  January 2006 

	January
	2006	Average	2005
Average maximum temperature (°C)	26.9	25.9*	26.6
Average minimum temperature (°C)	20.6	19.0*	19.6
Mean temperature (°C)	23.7	22.5*	23.1
Rain (mm)	121.4	103.0#	67.8
Number of rain days	19	12	15
Average daily sunshine (hours)	6.2	7.5	8.2

*Long-term temperature averages at Sydney (Observatory Hill) are from 1947 to present, due to a change at the site in that year.
# Median January rainfall is 80mm.
Climate averages for Sydney are available, here. 

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Australian 3-month Climate Outlook 1902 935 251 
NSW Daily Rainfall Bulletin 1902 935 223

Bureau's web site:   www.bom.gov.au