Temperatures to reach 40C as hot, humid weather hits Australia's east coast

The east coast of Australia is being hit with extreme heat on Wednesday, with high humidity in some areas making it feel even hotter.

A total fire ban is in place for much of the NSW coast as hot and windy conditions create the perfect conditions for blazes to take hold.

The Sydney CBD will hit a max of 33 degrees while out west Penrith and Richmond are set to reach 40C, and Campbelltown will reach 39. It will get to 37 at Parramatta.

Much of the east coast is set to be hit with extreme heat. Source: BOM

On Wednesday the forecast for the southeast coast of Queensland is "very hot", with daytime maximum temperatures to reach between 34 and 40.

There's a 60 per cent chance of showers and gusty thunderstorms set for the afternoon.

Toowoomba will soar to 39, as will Rockhampton with Longreach topping out at 45.

Storms are expected in Queensland on Wednesday afternoon while showers are expected in parts of NSW.

Many areas along the Queensland east coast can expect high humidity for most of the day including the Gold Coast, Sunshine Coast, Mackay, and Brisbane.

The humidity will also travel about 50 to 100km inland.

People are being warned to be safe and vigilant around waterways. Source: AAP / Stock image

The NSW Mid-North Coast inland will be hot with light winds, with daytime maximum temperatures tipped to reach between 33 and 38.

Total fire bans are in place for areas in and around Sydney and the Illawarra, the Hunter, Central Ranges, New England, Central West, Southern Highlands and the ACT.

The humidity in most Sydney areas is expected to drop off around early to mid afternoon as strong westerly winds begin to move across.

The Rural Fire Service urged residents to prepare their homes, follow bushfire survival plans and remain vigilant ahead of this week’s predicted strong south-westerly winds and high temperatures.

There's a total fire ban in place for most of NSW. Source: AAP

The above-average heat was too much to bear for most in Queensland on Tuesday, and NSW residents also suffered through muggy conditions on Monday and Tuesday with the humidity set to last much of the week.

"A cold front is expected to cross NSW today. Hot and dry fresh west to northwesterly winds are forecast ahead of the front, bringing severe fire danger to much of the state," a warning on the Bureau of Meteorology website says.

"The Brisbane CBD was about 26 on Tuesday night. That's 5 degrees above average, which doesn't sound that bad but with the humidity that felt like about 30 which is just yucky," Bureau of Meteorology (BoM) forecaster Annabelle Ford told news.com.au.