The climate of Sydney, Australia is humid subtropical (Köppen: Cfa), shifting from mild and cool in winter to warm and occasionally hot in the summer, with no extreme seasonal differences since the weather has some maritime influence. Contrasting temperatures are recorded in the western suburbs, as Sydney CBD is more affected by the oceanic climate drivers than the hinterland (due to moderation by the Pacific Ocean).
Despite the fact that there is no distinct dry or wet season, rainfall peaks during summer and autumn months, and is at its lowest just around the middle of the year, though precipitation can be erratic throughout the year. Precipitation varies across the region, with areas adjacent to the coast being the wettest. According to the Bureau of Meteorology, Sydney falls in the temperate climate zone with warm to hot summers and no dry season. Under the Holdridge Life Zones classification, coastal Sydney falls in the Subtropical Moist Forest zone and the inland, western suburbs in the Subtropical Dry Forest zone. According to Troll-Paffen climate classification, Sydney has a warm-temperate subtropical climate.Climatic map by Istituto Geografico De Agostini, according to Troll-Paffen climate classification Sydney's plant hardiness zone ranges from zone 11a in the east to 9b in the far west, with the majority of the region falling under 10b.
Sydney has 109.5 clear days and 127.2 cloudy days annually, though it has around 200 days of visible sunshine if partly cloudy days or sunny breaks are counted. Overall, Sydney has just about 66% of possible sun for Jun-Aug and around 54% for Dec-Feb, making winter sunnier than summer on average, in addition to the city being sunny around 65% of the time in the year with its 2,640 hours of annual sunshine. On some hot summer days, southerly busters decrease temperatures by late afternoon or early evening.Batt, K, 1995: Sea breezes on the NSW coast, Offshore Yachting, Oct/Nov 1995, Jamieson Publishing. In late autumn to early winter, the city can be affected by east coast lows.
Sydney experiences an urban heat island effect, making certain parts of the city more vulnerable to extreme heat, particularly the west. The El Niño Southern Oscillation, the Indian Ocean Dipole and the Southern Annular Mode play an important role in determining Sydney's weather patterns: drought and bushfire on the one hand, and storms and flooding on the other. Sydney is prone to heat waves and drought, which have become more common in the 21st century. The region of Sydney, and as well as the rest of the New South Wales coastline, is warmed by the East Australian Current. In 2023, Sydney was placed at 9th place by Stars Insider for having the best weather in the world.
Seasons
Summer
Summer is generally warm to hot, and often humid (particularly in late summer). The ultraviolet index rating averages at 12, but can reach 13 in the midst of the season, which may lead to skin damage among those having light skin.
Sydney can receive hot, dry northwesterly winds from the Outback that make the temperatures soar above . This happens after the northwesterlies are carried entirely over the continental landmass, not picking up additional moisture from a body of water and retaining most of their heat. On these occasions, the city can experience the fury of the desert climate, although they are often ended with a southerly buster, which is a windy, shallow cold front or a sea breeze that sweeps up from the southeast abruptly cooling the temperature. At times, it may be accompanied by a thunderstorm and drizzle, and it may keep the temperatures cool the following few days as well.Winds of Australia by Weatherzone. Accessed 1 July 2023.
In the Sydney central business district, an average of 15 days a year have temperatures of more than and 3 days with temperatures over . In contrast, western suburbs such as Liverpool and Penrith have 41 and 67 days with temperatures above , 10 and 19 days above , and, 1 and 4 days above , respectively.
The highest recorded maximum temperature at Sydney Airport was 46.4 °C (115.5 °F), which was on 18 January 2013. The highest recorded maximum temperature at Sydney CBD was recorded on that same day with the temperature climaxing at 45.8 °C (114.4 °F).City chaos as mercury hits record 45.8C by News.com.au. Retrieved 9 November 2024. The highest recorded maximum temperature within Sydney's Metropolitan area was recorded at Penrith with a high of 48.9 °C (120 °F), a Western Sydney suburb, on 4 January 2020. At that time, Penrith was the hottest place on the planet and the hottest temperature recorded within Australia and the Southern Hemisphere for all of 2020. A record high dew point was set on 11 January 2024 with a dew point of .
Autumn
Late summer conditions usually continue until the last week of March. Most heavy rainfall events usually occur in late summer and early autumn as the subtropical ridge of high pressure, which rotates counterclockwise, is to the south of Australia and therefore give way for moist easterlies from the Tasman Sea and as well as low pressure systems to penetrate the region. In the early 19th century, March was considered the wet season by explorer William Wentworth, as it was more prone to flooding than other months.Statistical, Historical, and Political Description of NSW by William Charles Wentworth, 1819
The transition from late summer to autumn is gradual, with noticeably cooler and crisper conditions taking in effect by around mid-April.Power, S., Tseitkin, F., Torok, S., Lavery, B., Dahni, R. and McAvaney, B. 1998. Australian temperature, Australian rainfall and the Southern Oscillation, 1910–1992: coherent variability and recent changes. Aust. Met. Mag., 47, 85–101 Temperatures in autumn are usually consistent and stable, lacking any extremes that tend to be experienced in spring and summer. Sydney's northern suburbs generally experience slightly cooler temperatures than the coastal suburbs, creating favourable conditions for deciduous trees. During autumn, suburbs such as Pymble and Turramurra are known for their colourful displays, particularly those of sweet gum trees.
The lowest maximum temperature in autumn is , recorded on 24 May 1904. The highest maximum autumn temperature ever recorded at Sydney Airport was recorded on 9 March 1983, with the temperature peaking at . Though the hottest autumn day ever recorded in Sydney's metropolitan area was on 6 March 1938 when Richmond RAAF hit .Richmond RAAF by the Bureau of Meteorology. Retrieved 9 November 2024.
Winter
Winter in central Sydney tends to be mild where the lows rarely drop below , mainly due to proximity to the ocean. Furthermore, Sydney CBD (Observatory Hill) has never recorded frost. In the far west (in places such as Richmond and Camden), the diurnal range can be relatively great, particularly in late winter. In the west, Liverpool and Richmond have 4 and 38 nights, respectively, where temperatures dip below . On average, only 1 night in Liverpool and 17 nights in Richmond have lows that go below . In such cold mornings, frost can form in the far western suburbs. The lowest maximum temperature in Liverpool was , recorded on 28 July 1981.
Sydney receives around 15 days of fog annually,The Great Australian Weather Debate! Which Australian City has the best weather? Gungahlin Weather Centre - March 2002. Retrieved 28 November 2029 which occurs in winter mornings; some can be thick enough to divert planes and cancel ferry services.Russell, H. C. 1877. Climate of New South Wales: Descriptive, Historical, and Tabular. C. Potter, Sydney, Australia. During late winter, warm dry westerly winds which dominate may raise the maximum temperatures as high as in some instances. As the subtropical ridge is north of Sydney in mid-to-late winter, it picks up dry westerlies from the continent's interior because of its anticlockwise rotation, thus producing more sunny days in the region.Evans, J. P., Ji, F., Lee, C., Smith, P., Argüeso, D., and Fita, L. (2014) A regional climate modelling projection ensemble experiment – NARCliM, Geoscientific Model Development, 7(2), 621-629,
The lowest recorded minimum at Observatory Hill was on 22 June 1932, while the coldest in the Sydney metropolitan area was , in Richmond. The lowest recorded maximum temperature at Observatory Hill was . Although not usually considered a suburb of Sydney, Picton, a town in the Macarthur Region of Sydney, recorded a low of on 16 July 1970. Sydney's warmest winter day was recorded on 30 August 2024 at Sydney Airport when the temperature hit at 2:48 PM.Sydney hits 30°C in winter by Anthony Sharwood from WeatherZone. Retrieved 9 November 2024.
Spring Early spring is rapidly transitional and erratic. Cool conditions from late winter may continue in September, but due to the drastic transition, temperatures above can also be expected in that month, including the odd thunderstorm. By November, summery conditions begin, albeit with relatively low humidity. Because the subtropical ridge lies to the north of Sydney this time of the year, it will bring westerly winds from the interior that produce mostly sunny conditions, with relatively low dewpoints. Extreme, changeable and inconsistent temperatures are much more prevalent in spring than other seasons. Furthermore, the diurnal range is higher in this season than it is in autumn.
The lowest maximum temperature in spring was , recorded on 8 September 1869. 9am relative humidity is the lowest in the year during spring, ranging from 58% to 68%, with early spring receiving lower figures. The highest maximum Spring temperature ever recorded at Sydney Airport was on 25 November 1982, when the temperature eclipsed at . Sydney CBD also recorded its hottest spring day on this same day, peaking at . The highest spring temperature recorded in Sydney's Metropolitan area was registered at Richmond on 23 November 2014, peaking at .
Climatic trends and extremes Early climate history
Palaeoclimatic evidence indicates that the climate of the Sydney region has changed considerably over geological time. During the Permian, the region experienced cold high-latitude conditions and periods of glacial influence, followed by substantial warming around the Permian–Triassic transition. During the Cenozoic, south-eastern Australia experienced periods of considerably warmer and wetter climate than at present, followed by a long-term trend towards cooler and drier conditions.
During the Quaternary, Sydney experienced substantial variations in temperature and precipitation associated with glacial–interglacial cycles and changes in regional atmospheric circulation. The early Holocene was generally drier than the later Holocene, while the last several thousand years have been characterised by considerable hydroclimatic variability. The Dharawal people traditionally recognise six seasons in the region based on recurring climatic and ecological conditions. Written observations of Sydney's climate began following European settlement in 1788, with Watkin Tench and later William Wentworth providing early descriptions of temperature, frost, rainfall, thunderstorms, winds and seasonal variations.
1980s–2000s