Temperatures have topped 37 degrees in parts of the Sydney metropolitan area on Tuesday afternoon, as a second surge of heat in three days fuels fires across New South Wales.

While a cold front crosses southeastern Australia, hot winds are being fanned ahead of this powerful system, with several NSW locations experiencing their hottest temperatures so far this spring.

• Sydney's main weather station at Observatory Hill reached 35.7°C on Tuesday, which exceeded the 35.6°C on NRL Grand Final day on Sunday
• Sydney Airport reached 37.2°C which beat Sunday’s 36.9°C
• The equal-hottest spot in the state on Tuesday was the tiny rural locality of Tocal in the Hunter Valley, which also saw 37.2°C

That means that the Sydney and Hunter regions were the hottest areas of New South Wales, which is unusual. Even more unusually, most of Sydney's coastal suburbs were as hot as the city's west – or even a little warmer.

To put Sydney's Tuesday heat in perspective, at one point it was almost 20 degrees hotter than Melbourne where the mercury had slipped into the mid-teens as the cooler air arrived amid steady rain.

When will this hot spell end?

Sydney will still see max temps in the mid-to-high-twenties on Wednesday before rain and cooler air arrives.

The biggest rainfall totals from systems like this tend to fall on the ranges or west of them, so thirsty Sydney gardens can expect a decent drop but probably not a soaking – unless storms form.

Meanwhile the map of NSW fires on Tuesday afternoon makes for grim viewing.

The two red symbols indicate Emergency Warnings – one for Kearsley in the Cessnock area of the Hunter Valley, the other at Coolagolite in the Bega Valley local government area.

Source: NSW RFS.

• Please note that Emergency Warning is the most serious of three fire alert levels issued by the NSW Rural Fire Service (RFS).
• It means you may be in danger and need to take action immediately. Any delay now puts your life at risk.

Firefighters in the northern part of the state may not get as much help as they need from the skies on Wednesday, but with heavy rain expected on the South Coast, a few prayers should be answered in that region.

There is also the chance of lightning strikes causing new fires in coming days, especially in the northern part of the state.

Please check the NSW RFS page here and our Warnings page here or on our app.