Tuesday, 1 June 2010 - Monthly Climate Summary for Sydney - Greater Sydney - Product code IDCKGC25L0

Wet end to Autumn

• Above average rainfall for coastal areas.
• Above average maximum temperatures.
• Warm night time temperatures on the coast and cool nights in the west.

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Rainfall

Sydney Observatory Hill recorded 168.4 mm in May which is above the historical average¹ of 100.6 mm. This has been the wettest May since 2003 (348.6 mm) and the wettest month since February 2010 (239.4 mm). The majority of the rainfall fell during four events; the first of which was on the 18th-19th, due to onshore SE flow combined with very much above average sea surface temperatures, and an upper level low pressure trough which contributed to thunderstorms and persistent moderate to heavy falls throughout the 18th (mostly constricted to coastal areas). The second event was on the 22nd-23rd of the month and was due to SE onshore flow and an upper level trough. More rain followed on the 26th-27th caused by a low pressure system off the NSW coast combined with SE winds, which resulted in moderate rainfall throughout the day. The final event on the 30th-31st was a result of a low pressure system which moved across from the far south coast of NSW to off the coast of central NSW affecting Sydney's weather. Very much above average sea surface temperatures along the NSW coast have contributed to the high humidity and rainfall for all of these events. The wettest day of 83.0 mm was recorded at Cronulla South Bowling Club on the 19th of the month. This was also the wettest part of Sydney overall recording 302.8 mm for May.

Sydney's storage levels have dropped to 56.3% following a dry April. Although many locations received above average falls, most of the rainfall events were constricted to the coast. 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 16.4°C which is 0.2°C above the historical average¹ of 16.2°C. During the first half of the month temperatures were above average with mostly fine conditions due to the passage of several high pressure systems. The first cool change came through on the 12th with mostly below average temperatures recorded from the 17th till the end of the month. Cloudy conditions associated with four rainfall events in the second half of the month contributed to the cooler than average maximum temperatures. Coastal areas recorded mostly above average minimum temperatures due to the higher humidity, which is a result of higher than average sea surface temperatures. The onshore flow was mostly restricted to coastal areas with western parts of Sydney recording mainly below average minimum temperatures.

Maximum temperature

Sydney Observatory Hill recorded an average maximum temperature of 20.6°C which is 0.3°C above the historical average¹ of 20.3°C. This is the warmest May since 2009 (20.7°C). Warm conditions were experienced across the Sydney basin with Campbelltown recording the warmest daily and monthly average maximum temperature of 27.2 °C and 21.2 °C respectively.

Minimum temperature

Sydney Observatory Hill recorded an average minimum temperature of 12.1°C which is 0.1°C above the historical average¹ of 12.0°C. The warmest minimum temperatures were recorded at Sydney Observatory Hill with the warmest night of 16.2 °C also recorded at Sydney Observatory Hill on the 4th on the month.

Wind

Prevailing winds in coastal Sydney during the afternoon (3pm) were between E and S for 48% of the time during May which is very close to the normal frequency from this direction of 49% (observations taken from Sydney Airport).

Other phenomena

There was a total of 2 thunderstorms recorded in Sydney which is above the historical average¹ for May. Sydney Observatory Hill recorded an average of 5.7 hourswhich is slightly below the historical average¹ of 5.9 hours per day.

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