Temperatures reached close to 50 degrees as a mass of hot air hung over the state, sparking heatwave and extreme fire danger warnings.

Oodnadatta recorded its hottest day in 65 years after it reached a top of 48.7 degrees Celcius, followed by Coober Pedey at 48.1 degrees, Tarcoola at 47.8 degrees and Port Augusta at 46 degrees.

Those four suburbs made the top 10 hottest places on the planet today.

Adelaide topped the charts as the hottest city around the globe for large parts of the day.

”Very hot just about everywhere, even by the coast which usually does get a bit of relief with sea breezes,” the Bureau of Meteorology’s Simon Timcke said.

“Whilst we do usually get hot weather in February, this is a bit hotter than we’d often see.”

The uncomfortably hot weather closed down cafes and construction sites around the city and also affected public transport, with trains forced to reduce their speed and eight tram services cut during peak hour.

“Gross, so gross. Like even walking here it was just so unbelievably hot,” resident Samara Dickson said.

A cool change is now being felt over the state as a low-pressure system sweeps eastward.

Tomorrow, temperatures are forecast to reach a cooler top of 27 degrees.

A heatwave warning remains for the state, and an extreme fire danger warning is in place for the West Coast, Eastern Eyre Peninsula, Lower Eyre Peninsula and Mount Lofty Ranges areas.

Other southeastern capitals felt the warmth today and will continue to see high temperatures through the week.

Melbourne saw a top of 35 degrees today, with 37 degrees forecast the following day, before a cool change on Thursday night.

Hobart is also likely to hit the mid-30s on Thursday.

High fire danger is also predicted for parts of western Victoria too.