Monday, 3 May 2010 - Monthly Climate Summary for Sydney - Greater Sydney - Product code IDCKGC25L0

Unseasonably warm and dry April

• Very much above average maximum and minimum temperatures.
• Below average rainfall.
• Equal 7th warmest April on record.
• Equal 6th warmest April on record for average maximum temperatures.

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Rainfall

Sydney Observatory Hill recorded 30.0 mm in April which is well below the historical average¹ of 132.9 mm. The overall dry conditions were partly due to the passage of several high pressure systems which brought mostly fine weather to Sydney and blocked any potential troughs or frontal systems. The rain fell on 10 days which is below the historical average¹ of 12 days. The rainfall distribution over the Sydney area varied only slightly with most areas recording between 5 to 30 mm which corresponded to mostly below to very much below average rainfall for these areas (for more information see summary statistics table below). The wettest day in April was the 25th where locations such as Sackville recorded just over 20 mm during the passage of a cold front.

Sydney's storage levels have dropped to 57.6% following a dry March. Recent rainfall and current levels in Sydney's water catchments can be found on the Sydney Catchment Authority web site http://www.sca.nsw.gov.au/dams/rainfall.html

Temperature

Sydney Observatory Hill recorded an average mean temperature (average of maximum and minimum temperatures) of 20.2°C which is 1.0°C above the historical average¹ of 19.2°C. This is the equal 7th warmest April on record and the warmest since 2004 (20.2°C). The above average temperatures are a result of the passage of several high pressure system ridging across the NSW coast which brought mostly fine conditions across Sydney. A lack of any significant cool changes throughout April contributed to the build up of heat and persistent warm condtions. Sea surface temperatures off the NSW coast have been above average and have contributed to the higher humidity which has kept temperatures above average particularly at night. A moderate El Niño in the Pacific ocean combined with human induced global warming have also contributed to the above average temperatures.

Maximum temperature

Sydney Observatory Hill recorded an average maximum temperature of 24.6°C which is 1.4°C above the historical average¹ of 23.2°C. This is the warmest April since 2006 (24.6°C) and ranks as the equal 6th warmest April on record. Warm conditions were experienced across the Sydney area with Penrith recording the warmest average maximum temperature of 25.5°C. The highest daily maximum temperature recorded was 31.5°C at Bankstown Airport on the 22nd of the month.

Minimum temperature

Sydney Observatory Hill recorded an average minimum temperature of 15.9°C which is 0.7°C above the historical average¹ of 15.2°C. This is the warmest April since 2002 (16.4°C). Warm minimum temperatures were recorded across the Sydney basin with Sydney Observatory Hill recording the warmest average minimum temperature across greater Sydney. The warmest daily minimum temperature was 20.2°C recorded at Sydney Observatory Hill on the 24th of the month.

Wind

Prevailing winds in coastal Sydney during the afternoon (3pm) were E and S for 66% of the time during April which is above the normal frequency from this direction (observations taken from Sydney Airport).

Other phenomena

On the morning of the 21st of the month fog was observed at many locations across greater Sydney.

Details Extremes Records Summaries Important notes the top

Details Extremes Records Summaries Important notes the top

Details Extremes Records Summaries Important notes the top

Daily rainfall

Most values are the precipitation in the 24 hours to 9 am on the day indicated. Days marked with »» are part of a longer accumulation, which is marked like this on the final day. Values over 100 mm have been rounded to the nearest whole millimetre. Days marked with - have a rainfall report of zero; days left blank have no rainfall report (which often indicates no rain fell).
This table is very wide; you may have to scroll sideways to see all the days, and you may need to set the paper to 'landscape' to print.

Details Extremes Records Summaries Important notes the top