A large fire has started burning out of control during a 40-degree heatwave on Sunday in the Sydney suburb of Northmead, near Parramatta.

Families have been evacuated from the area near Whitehaven Road as firefighters attempt to control the blaze.

It’s just one of 45 bush and grassfires burning across NSW during the heatwave, with smoke already noticeable in Sydney.

“It’s a very different season,” NSW RFS Commissioner Rob Rogers told reporters on Sunday.

“What we haven’t had for the last few years is grass because we have been in a drought so there’s been no grass to obviously grow or burn. That’s changed significantly.

“These grass fires are quite dangerous.”

Meanwhile, NSW Police Minister David Elliott was more blunt: “Here we go again.”

“We have of course seen the first weekend of really significant bushfire activity,” he added.

“I want to make sure the message is very, very clear. What we are seeing this weekend is pretty consistent with what we will potentially see over the course of this fire season.”

Firefighters used waterbombing aircraft to contain the fire well into the afternoon, while about 20 firefighters battled the blaze on the ground.

The threat to properties has eased, according to the RFS, but things are still serious, and residents are still being urged to look out for embers, particularly amid unusually strong winds of up to 100 km/h which could potentially fan the flames.

This weekend was the first time Sydney experienced two consecutive November days above 40 degrees in 160 years of modern record keeping.

And it’s not just Sydney that’s getting hammered by unfavourable conditions, either.

Farmers elsewhere around the state have also been told to double check the weather conditions before harvesting crops.

Let’s hope the lessons learned from last year will prevent those same mistakes being made.

Image: Twitter / @9NewsSyd