Cool change ends misery at gates of Hell

If the forecasters are right, purgatory ended last night.

The cool southwesterly change predicted to roll up the east coast of Australia has arrived in Adelaide - ending that city's five-day heatwave with a humid cloak - and was yesterday pushing rain across the state.

Today, Adelaide can begin breathing again, with a fine, partly cloudy day and a predicted, blissful, 26C - a dramatic drop on the temperatures that have been searing the city.

The front will move on to Victoria, reducing the catastrophic fire risk that has scraped nerves raw and forced people from homes and campsites.

After a Monday high of 43.6C in Melbourne and 45C in several parts of the state, air conditioners and fans worked overtime as Melbourne endured its hottest night since 1902, at 32.3C.

Victorians sweltered again yesterday, and many areas topped 40C.

But the cooler weather is expected to arrive in Melbourne today, and the forecast high has tumbled to 23C.

It will be warmer in Sydney and Canberra today - about 30C - but showers and further falls in temperature will bring a welcome break in the run of furnace-like heat that has pushed people and the services they need to the limit.

For the past two days Canberra has baked in temperatures officially peaking at 38C but unofficially higher in the suburbs as northwest winds turned the city into a fan-forced oven.

There is almost no escape.

Apart from the unfortunates forced to work in the open, people avoid the sun and walk the streets as little as possible, seeking whatever shade is available.

Canberra is a typical inland Australian city, 160km from the sea and cut off by the distant Clyde Mountains, sitting in the low valleys of an undulating interior.

In the open, the heat dehydrates within minutes. It is a raspy, dry blast that scrapes the skin and burns mercilessly if you are exposed too long.

Without the wind, the heat is all but unendurable. Add the wind, and it is a searing shock that hits like a heat gun as you step out of air-conditioned buildings.

Health warnings are repeated. We are told the symptoms of heat exhaustion, the risk of which mounts as the hot days roll on one after the other - heavy sweating, muscle cramps, tiredness and weakness, dizziness, headaches, nausea and fainting.

Animals are also suffering.

I have been bringing my daughter's Staffordshire terrier into the house during the day.

Even with good shade, its body is hot to the touch by mid-morning, and even in the shelter of the house its normal hyperactive personality has been replaced by deep torpor.

Shopping centres are filled with people - many of them mothers with children - taking advantage of the air conditioning.

Fortunately - and unusually for Canberra - we have had cool nights.

But as soon as the sun rises, all windows and doors are shut, thermal curtains are drawn, and fans whirr throughout the day.

The cool change cannot come soon enough.

* In eastern Victoria last night, the cool change eased the menace from a a bushfire that jumped containment lines and was threatening homes in the East Gippsland towns of Cann River and Lower Tonghi.

Fire fighters earlier visited rural homes in the area to warn of the danger from the out-of-control blaze.

But early this morning (NZT) they said the wind speed and temperature had dropped, enabling them to gain control of the 60ha fire.

- ADDITIONAL REPORTING: AAP