The SMCMA area is dominated by a temperate maritime climate characterised by warm summers and cool winters.  Sydney's annual average of sunshine is almost seven hours a day.  The maximum average summer temperature for Sydney is 25 celcius, with the minimum average summer temperature 18 celcius.  The maximum average winter temperature is 16 celcius and the minimum average winter temperature is 8 celcius.

Annual average rainfall in Sydney is approximately 1,220 mm, with more than one third of this falling between March and May.  The average number of wet days each month is 12.  Summer rainfall occurs in the form of a small number of storm events with each one providing high volumes of rainfall.

Yearly pan evaporation for the region is 1,800 mm.