If you think Sydney just had an unusually hot start to summer, you weren’t imagining it. The city just experienced its hottest first fortnight of summer in more than 160 years of records.

Thursday was a sweaty day across the Sydney Basin, with temperatures reaching 38.9ºC in the city and 40.3ºC at the airport by 4pm. This hot weather was exacerbated by high dew point temperatures, which made conditions feel muggy during some parts of the day.

Image: Forecast maximum temperature on Thursday, December 14, 2023.

Thursday’s heat capped off a very warm fortnight in Sydney, with the city climbing above 26ºC every day during the last two weeks and reaching around 40ºC twice. As the ABC’s Tom Saunders pointed out, this has been Sydney’s hottest start to summer on record.

Sydney’s average maximum temperature during the first 14 days of summer was 29.5ºC, which beats the previous record of 28.9ºC from the first fortnight of summer in 1976. Data at Sydney’s Observatory Hill dates back to 1859.

Sydney’s record hot start to summer was caused by a stagnant area of high pressure over eastern Australia, which allowed hot air to linger across NSW. A pool of abnormally warm water in the western Tasman Sea also helped limit cooling in the coastal city over the past fortnight.

Unfortunately for Sydneysiders that are sick of being sweaty, daytime maximum temperatures are forecast to reach 27 to 33ºC from this Friday and at least the middle of next week.