THE heatwave Sydney has managed to avoid is due to hit on Tuesday, as firefighters prepare for the most dangerous bushfire conditions in years in the city and around the state.
The Bureau of Meteorology is predicting the maximum temperature in Parramatta and the western suburbs will be 43 after a run of much cooler days.
The temperature peaked at 28 in the city and 34 in the western suburbs on Sunday, and it is predicted to top 27 in the city and 33 in the west on Monday.
Sydney escaped extreme temperatures for much of the past week because of easterly winds bringing cool air from the ocean, the bureau's duty forecaster, Sarah Hicks, said.
''Those winds will move to the west, so that usually brings hotter inland temperatures through to the coast,'' she said.
Some of the hottest areas in the state at the weekend were in the far west and the southern half of the state, including Hay, which set a record at 48 on Saturday, Ivanhoe, which hit 45, and Wilcannia, which hit 47.6 on Sunday.
A NSW Rural Fire Service spokesman, Ben Shepherd, said the hot and windy weather meant fire ratings in Sydney, the Illawarra, the Shoalhaven, central ranges and parts of the Riverina could be extreme on Tuesday.
Mr Shepherd said those were the highest fire danger ratings the regions had had in years, while almost half the state could have severe fire danger ratings and total fire bans.
''The last few years of wet weather have led to unprecedented growth in some areas in the western parts of the state. That grass has now dried out,'' Mr Shepherd said. ''It's now become very susceptible to fire. It's in areas now that haven't seen fire activity for decades.
''Some people don't believe they're as dangerous as bushfires but grass fires typically move around about three times as fast as a bushfire. They can cut roads and impact on properties with little or no warning.''
RFS volunteers fought about 70 blazes across the state on Sunday.
Grass fires sparked by lightning strikes were burning in Stuart Town, near Wellington, and Numeralla, east of Cooma. Firefighters have been preparing for weeks for the extreme heat, and the service has water bombing aircraft on standby.
''What we're asking, though, is the public take this opportunity to prepare themselves,'' Mr Shepherd said. ''Clear the gutters, trim back trees, have a hose that reaches the whole way around your home but, most importantly, have a bushfire survival plan.''
There is likely to be little relief from the heat around NSW for at least a week. Despite relatively cooler temperatures spreading from coastal areas to the south of the state after Tuesday's highs, the weekend was expected to bring more sweltering conditions, Ms Hicks said. ''We've got quite a lot of hot upper air over the inland of the state and it's just not really cleared out by that change that comes through on Tuesday and Wednesday,'' she said.