The Climate of Sydney
With the exception of Antarctica, no continent has less liquid water than Australia. Rather than having seasons, Australia has a staggering hiccoughing cycle of El Niņo events, with droughts and flooding rains, such as Dorothea Mackellar describes in My Country. One of the long-standing themes in Australian rural culture is a hatred of "the Banks", much of it stemming from the way in which banks lend money on an annual basis, and repossess properties when the money cannot be paid back until the end of that particular drought cycle.
About 70% of the continent is classified as arid or semi-arid, and eleven large deserts make up about 20% of the mainland. These are not "deserts" in the popular image of featureless sand, but rather, they are sandy or stony, but they also carry plants and animals, and after rain, they can be breathtakingkly beautiful, but Australia's deserts are not a place to stray on your own.
Across the continent, the average rainfall is a mere 465 mm, about 15 inches, as low as 125 mm (5 inches) in the Lake Eyre drainage basin. Western NSW can record temperatures over 50° C (122° F), and the highest ever recorded was 53° C (128° F) at Cloncurry in 1889. The coldest temoperature ever recorded was -23° C at Charlotte Pass near Mount Kosciuszko in 1994.
While it can snow in January near Cradle Mountain in Tasmania, and while you may need a sweater on the Great Barrier Reef in July, most parts of Australia are pleasant and predictable most of the time.
Historically, we average a metre of rain, 40 inches, each year, but few years are average years. There is no rainy season, and the rain usually goes quickly, but sudden storms can be common, and "showers" means downpors in some places and nothing a few hundred metres away. Learn to live with it.
Sydney is in the southern hemisphere: if you are from the northern hemisphere, remember that the seasons are reversed. Our hottest months are December to February, during the southern summer. Our flowers largely ignore the seasons, so you can usually see about 30 species in flower as you walk along a suburban street, and at least that number species of wildflower can be in bloom any time from May to December, with a few less in January-April. The best time for wildflowers is in August, when a walk over a headland can reveal 60 species in bloom.
In summer, the temperature can reach the high 30s on a bad day, and will occasionally drop down to 17 at night, but the summer temperatures are more typically somewhere in the twenties.
In winter, the temperature can go as low as 5 degrees, with a wind chill factor on top of that, and reach freezing away from the coast. Even so, a winter's day when the temperature fails to reach 15 degrees is a cause for grumbling. The temperature, in other words, is generally mild. If you need to wear a coat, be prepared to take it off later, and if it isn't coat weather, it might be handy to carry something warm, as you may need it later, especially if a southerly change comes in.
There are people who swim the whole year around in Sydney, but these are generally regarded as eccentric: few people swim in June, July or August. Board riders surf all year around in wet-suits, and people will lie on the sand or paddle in the shallows all through the year.
Northern hemisphere weather watchers should note that winds go clockwise around our lows (and anti-clockwise round a high), and that warm fronts are very rare events.
Hail happens in Sydney a few times each summer, usually as part of a spectacular thunderstorm, and the hailstones can and do occasionally damage cars. There will usually be warnings on the local radio stations before a hailstorm reaches you.
Snow is seen in winter maybe once every five years, but you need to be an expert to recognise the three or four flakes that fall. Snow is usually seen once or twice each year in the Blue Mountains, where they usually get enough snow to build the odd snowman. There is skiable snow in Australia, though, but if you want to go skiing, head for the Snowy Mountains, 500 km south of Sydney, between June and October. If you won't do that, then you'd better settle for some water-skiing.
For detailed conditions, month by month, see the weather page.
This file is http://members.ozemail.com.au/~macinnis/syd/climate.htm, first created on February 28, 2006. Last recorded revision (well I get lazy and forget sometimes!) was on October 9, 2006.