Climate of Sydney - Precipitation

Precipitation

Rainfall is fairly evenly spread through the year, but is slightly higher during the first half of the year when easterly winds dominate (Feb-Jun), and lower in the second half (mainly Jul-Sep). The average annual rainfall in the city, with moderate to low variability, is 1,217 mm (48 in), falling on an average 138 days a year. As seen from the climate table above, Sydney's wettest month is June, though most of its western suburbs' wettest month is February. The driest months are July through to September. Snowfall was last reported in the Sydney City area in 1836. However, a July 2008 fall of graupel, or soft hail, mistaken by many for snow, has raised the possibility that the 1836 event was not snow, either.

Even in its months of highest rainfall Sydney has very few rainy days, on average less than 14 rainy days per month. This means the average rain event in Sydney contains heavy rain. The city is not affected by cyclones, although remnants of ex-cyclones do affect the city. The El Niño Southern Oscillation plays an important role in determining Sydney's weather patterns: drought and bushfire on the one hand, and storms and flooding on the other, associated with the opposite phases of the oscillation.

The city is prone to severe hail storms, wind storms, and flash flooding from rain caused either by East Coast Lows (during autumn-winter periods) and Ex-Tropical Cyclone remnants (during spring-summer periods). They are low pressure depressions that can bring significant damage by heavy rain, cyclonic winds and huge swells.