The NSW capital woke up to an abnormally hot March morning, with temperatures already topping 28 degrees before sunrise.

Temperatures are set to spike at a record high of 37 degrees for a mid-March day, making it the hottest capital city today by far.

Suburbs in western Sydney will face the hottest temperatures, including Penrith and Campbelltown, while Sydney city will sweat under the mid to high 30s too.

The Bureau of Meteorology issued a heatwave warning for all of metropolitan Sydney, with a low-intensity heatwave across NSW extending as far as Broken Hill and Albury.

Kiama on the south-coast was NSW’s hottest area earlier this morning, with temperatures already at 32 degrees just after 8am.

Today’s heatwave conditions are expected to linger until midnight and a cool change is expected for tomorrow.

“Today is the hottest day, and then it is the end – well, that is the hope,” said senior meteorologist Magda Gallos-Lorenc.

The heat has prompted a total fire ban across greater Sydney, the central ranges, southern slopes and southern ranges regions.

Dry and hot wind gusts today could exacerbate any fires and the Rural Fire Service has advised any residents in high-risk areas to activate their survival plan.

NSW Ambulance has also warned Sydneysiders to avoid going outside during the warmest times of the day, which is around 1pm today.

“Stay hydrated and avoid outdoor activities during the hottest parts of the day,” NSW Ambulance said in a warning.