After a blisteringly hot day, parts of New South Wales have sweated through their hottest November night in many decades.

On Saturday a low pressure trough directed a very hot airmass from the interior over New South Wales. Cloud increased during the day and this coupled with strong northwesterly winds minimised nocturnal cooling, trapping much of the day's warmth.

Image: High 850hPa temperatures over NSW at 2am Sunday from the ECMWF model.

Sydney had an overnight low of just 25.3 degrees (9.6 above average), just after 1am on Sunday. This was the highest November minimum in the 162 years of records and the highest of any month in nearly four years. Elsewhere in the Sydney Basin, Bankstown's low of 28.3 degrees was the highest in Sydney and is 13.9 above average, making it the hottest November night in 49 years. 

It was a similar story up and down eastern New South Wales. In the Hunter, Mangrove Mountain dropped to just 25.5 degrees (11.7 above average) and Nobbys Head dipped to 24.1 (7.7 above average). These were the hottest November nights in 23 and 60 years respectively. In Ulladulla (South Coast) the low of 20.6 degrees was the highest in November since records began in 1990.

Although not as widespread, western parts of the state also had very warm nights. In the Upper Western, some towns failed to drop below 30 degrees including Bourke, where it only fell to 31.3 which is 13.9 above average.

For those along who have trouble sleeping in oppressive conditions, relief is on the way in the form of a vigorous southerly change. The change will roar along the New South Wales coast on Sunday, reaching Sydney late afternoon.