With an estimated one million people preparing to descend on Sydney Harbour for New Year's Eve, forecasters are predicting a warm and humid end to 2018.
In the Sydney CBD itself the Bureau of Meteorology favours a cloudy, humid Monday with temperatures similar to Sunday and reaching the high 20s to low 30s.
There is the chance of a light shower in the early afternoon to evening for the city but it will hopefully clear in time for the fireworks.
There is also the slight chance of a thunderstorm over western Sydney, a Bureau spokesman told AAP.
However those on the harbour will likely only see some lightning flashes and hear thunder as a worst case scenario.
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For most other areas of the state apart from the far northeast, a light shower or thunderstorm is forecast mainly during daylight hours but there shouldn't be much rainfall as a result.
The upper western district including Bourke will be the hottest part of the state and will reach low to mid 40s.
The central west slopes and plains are forecast to climb into the mid 30s to low 40s.
The Hunter and western Sydney are also expected to reach the high 30s and the Riverina, low to mid 30s.
Further south, the Illawarra and ACT will mainly enjoy temperatures in the high 20s.
