Sydney sits on the southeast coast of Australia around Port Jackson harbour, at approximately 33.87°S, 151.21°E. It has a humid subtropical climate (Köppen Cfa) with warm summers and mild winters, moderated by the Pacific Ocean so that extremes are rare near the coast. Being in the Southern Hemisphere, its seasons are reversed relative to Europe and North America, and its western suburbs run noticeably hotter than the harbour-cooled centre.

Summer, from December to February, is warm to hot and humid, with January and February the warmest months — average highs around 26°C, though hot spells driven by desert air can send temperatures into the high 30s or past 40°C. February is the most humid month. On sweltering days a welcome 'southerly buster' can sweep up the coast in the late afternoon and drop the temperature sharply. UV is extreme in summer, regularly hitting 12–13.

Winter, from June to August, is mild and often sunny rather than harsh. July, the coldest month, averages daytime highs around 17–18°C with nights near 8°C, and temperatures on the coast rarely fall below about 7°C. Genuinely cold days are uncommon, and Sydney is often sunnier in winter than in summer, though the snowfields are only a few hours' drive inland.

Sydney is fairly wet, receiving roughly 1,000 mm a year with no true dry season, but rainfall peaks in the first half of the year — late summer and autumn — when warm easterly winds carry moisture off the Tasman Sea, and is lowest around September. Rain often comes in short, heavy bursts lasting a couple of days, and totals swing widely from year to year with El Niño and La Niña; 2022 was the wettest year on record at over 2,500 mm. Live rainfall, humidity, and pressure readings for the city are shown in the panels above.

Sydney's weather is strongly shaped by large-scale climate drivers: El Niño tends to bring drought and bushfire risk, while La Niña brings storms and flooding. In late autumn and early winter, powerful 'east coast lows' can deliver torrential rain and damaging seas. It is also the windiest of Australia's capital cities, and the western suburbs experience a marked urban heat-island effect.

To follow any single measurement in Sydney more closely, use our live instruments: the online barometer for atmospheric pressure, the thermometer for temperature, the hygrometer for humidity, the anemometer for wind speed, the wind vane for wind direction, and the rain gauge for rainfall.