2013 NRL Grand Final - Roosters v Sea Eagles
SYDNEY, AUSTRALIA - OCTOBER 06: (L-R) Norm Provan and Arthur Summons pose with the Grand Final trophy before the 2013 NRL Grand Final match between the Sydney Roosters and the Manly Warringah Sea Eagles at ANZ Stadium on October 6, 2013 in Sydney, Australia. (Photo by Cameron Spencer/Getty Images)

Stiffling heat is forecast for Sunday's NRL grand final, with the threat of the day's earlier games being delayed.

After three years where Sydney has barely had a summer, the hot weather has come early this year. September has been hotter and drier than the average year, and the first day in October is set to see the mercury rise into the mid-30s.

The current Bureau of Meteorology forecast is for temperatures to climb to a maximum of 36 degrees at the Sydney Olympic Park with a north westerly wind to pick up and not help matters.

Often winds from the North West - blowing out of the New South Wales outback - make things feel hotter than they are.

The current forecast reads: "Mostly sunny. Winds northwesterly 30 to 45km/h becoming light in the evening then becoming southerly 15 to 20km/h in the late evening."

The wind change isn't likely to come early enough to be of any benefit to the players.

The hour-by-hour forecast from the Bureau currently reveals that the temperature will be 33 degrees at 1pm, and will rise to 36 degrees at 3pm and 4pm before finally dropping back to 35 degrees at 5pm and 33 degrees at 6pm.

As the sun sets on the first day of daylight savings, the temperature is forecast to be 31 degrees at 7pm ahead of NRL kick-off at 7:30pm (AEST) and it'll still be 25 degrees at 10pm, which is after the scheduled fulltime.

While the men's NRL game itself is unlikely to be delayed, the competition have already flagged the need for extra drinks breaks and an extended halftime pending on the heat stress index. The day's earlier games - being the State Championship and NRLW - are almost certain to be impacted in one way or another even if they aren't delayed.

The NRL's head of football on Monday said contingency plans are available, with the NRL having plenty of time worked into Sunday's schedule in case of delays.

Accor Stadium have also been busy preparing with extra bottles of water purchased ahead of an expected spike in sales on match day as fans attempt to beat the heat.

The grand final is completely sold out, with gates to open at 1pm (AEST) on Sunday.

All forecast data taken from the Bureau of Meteorology and is correct at 9am (AEDT) on Sunday, October 1.