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Sydney's hottest March night in 110 years

Joel Pippard, Sunday March 16, 2025 - 11:33 AEDT


Sydney has sweated through its hottest March night in 110 years, after the mercury stayed above 25.9°C during the night.




Sydney Observatory Hill failed to cool under 25.9°C overnight into Sunday morning


However, it was cooler at 9:20am on Saturday, so the official 24-hour minimum temperature was 24.5°C


This is still the hottest March min temperature since 1915, and the fourth hottest on record


The hottest March min temperature was 25.7°C on March 26, 1871. Records have been kept for 166 years


It was also Sydney’s hottest min temperature of any month since November 2020




This heat was brought ahead of a strong cold front that has been funnelling a late-season heatwave over much of the south and east of the country over the past few days.


After temperatures reached 31°C in the city and 38°C in Penrith on Saturday, clouds helped to trap some of the heat in overnight. In addition, light north-northeasterly winds and Sydney Observatory Hill's proximity to the warm water in Sydney Harbour ensured the warm conditions lingered overnight.


Some other notable minimum temperatures across southeastern Australia were:




26.6°C in Mildura, Vic - their hottest March night in 42 years


27.6°C in Griffith, NSW - their hottest March night in 35 years


25.1°C in Renmark, SA - their hottest March night in 19 years




On Sunday, northwesterly winds are picking up and are forecast to keep out a seabreeze for the city, and possibly even for the beaches and coastal fringe in Sydney. The lack of a seabreeze will mean a consistent maximum temperature across the Sydney Basin, with both the city and Penrith expected to reach 37°C.





Image: Forecast maximum temperatures for Sunday March 16th from ECWMF


The gusty winds and high temperatures also mean there are for Greater Sydney and Southern Slopes regions today, with total fire bans in place.


This heat will get pushed out by a late but characteristic southerly buster, expected around 11pm. Despite being so late in the evening, a temperature drop of about 8-12 degrees in the first hour after the change is still expected, along with wind gusts exceeding 80km/h. Those along the coast should keep an eye out for a severe weather warning that may be issued for this change.


24-hour min vs running min


In Australia, official minimum temperatures are taken as the lowest temperature recorded in the 24 hours from 9am the previous day to 9am the current day. This methodology has been in place for hundreds of years and allows comparisons with much older readings. However, it is sometimes not very intuitive to interpret when there is a hot minimum temperature (or a cold maximum temperature), such as in this case.


The graph below shows Sydney’s temperature over the 24 hours to 9am and shows the difference between the official 24-hour minimum and the running min, a value the BoM uses to highlight the lowest temperature between 6pm and 9am.





Image: Sydney Observatory Hill temperatures from 9am Saturday to 9am Sunday, showing the difference between the running min temperature and the official min temperature.


While the running min is more intuitive for interpreting how hot a night felt to people, the official minimum is still important to keep track of to see changes in temperatures over time.


Regardless of the semantics, this was a sweltering night across Sydney and much of the southeast, and will be replaced by significantly cooler weather over the coming days as the cold front moves through.


- Weatherzone

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Sydney's hottest March night in 110 years

11:33 AEDT Sydney has sweated through its hottest March night in 110 years, after the mercury stayed above 25.9°C during the night.

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