Nobbys experienced a record five days over 30 degrees in September, Bureau of Meteorology data shows.
Weatherwatch meteorologist Don White confirmed this had never occurred before in 65 years of records.
"Australia had its hottest and driest September ever. In the coastal Hunter, it wasn't a lot different," Mr White said.
"That followed from a warm winter, so we're heading for 'hot, hot, hot' it looks like."
The highest temperature last month at Nobbys was 32.7 degrees on Sunday, September 17.
The record for Nobbys for that month - set on September 26, 1965 - was 34.4 degrees. That year, only two days were recorded over 30 degrees in September.
The data also shows Nobbys recorded four days over 30 degrees in September 2003. But in data that goes back to 1957, no other years recorded four or five days over 30 degrees in September.
On Tuesday, Nobbys hit 30 degrees at midday before the mercury began to fall, while 35 degrees was recorded at Maitland at 1.15pm.
Wind gusts of 33km/h were recorded at Nobbys and 52km/h at Cessnock Airport.
The bureau issued a gale warning for the Hunter coast for Tuesday and Wednesday.
Bureau meteorologist Peter Stapleton said this wind warning was expected to continue "at least until the end of Thursday".
Mr Stapleton said a low pressure system was forming, but the Hunter was expected to receive only five to 10 millimetres of rain.
He added that a hazardous surf warning was expected on Thursday, with a north-easterly swell that was "a little bit unusual".
The bureau also issued a fire weather warning for the Hunter on Tuesday, with "hot and dry strong and gusty north to north-westerly winds".
Mr Stapleton said strong winds coming through the Hunter Valley "pushes warm air from the interior to the coast and acts to keep out the typical early afternoon sea breeze".
Total fire bans were in place on Tuesday and the risk of fire was ranked "extreme".
A maximum of 29 degrees is forecast for Newcastle on Wednesday, with a high chance of showers and thunderstorms in the afternoon and evening. Temperatures are expected to fall to 21 degrees by Saturday.
Maitland is forecast to hit 30 degrees on Wednesday and 20 degrees on Saturday.
"The wind will make it feel a bit colder than the thermometer suggests on Thursday and Friday," Mr Stapleton said.
The bureau's latest long-range forecast said "October to December rainfall is likely to be below median for much of Australia".
Maximum temperatures for this period are "at least three times as likely to be unusually warm for most of Australia".
And minimum temperatures are "very likely to be above median almost nationwide".
The bureau declared an El Nino weather pattern, with its hot and dry conditions, a fortnight ago.
"Climate models indicate this El Nino is likely to persist until at least the end of February. Global warming continues to influence the Australian and global climate," the bureau's latest climate driver update said.
