Southern Tasmanians are being urged to take care this week, with a run of temperatures forecast to break a long-standing record.
The director of Public Health said the unseasonably hot conditions could lead to health issues for both the very young, and the very old.
The weather bureau's Tim Bolden said it was shaping up to be the first time Hobart has recorded six consecutive days on or above 25 degrees Celsius in November in nearly 130 years.
"[We'll break the record] if we make it to the six days that we're currently forecasting over 25 degrees — since last Saturday up until Thursday — and it's certainly looking very likely," Mr Bolden said.
"[We are] currently forecasting 28 for Tuesday, 29 for Wednesday and 29 for Thursday, having reached 30 last Saturday, 27 on Sunday and 27 on Monday.
"If we make it to that stretch of six days above 25 degrees, that would be a record heat spell for November, and equal to the maximum heat spell for the Hobart area that we've ever seen.
"So it's looking like a very significant event."
The heatwave is being caused by a high pressure system over the Tasman Sea.
"At this stage it looks like it's going to be for the remainder of this week, and it's not really until early next week that we see that high move out," Mr Bolden said.
Heatwave health warning for the young and old
Director of Public Health Dr Mark Veitch said people should check on older family members and friends for symptoms of heatstroke, with temperatures expected to exceed 30 degrees in some locations.
"High temperatures can knock people about, can certainly make people who are older or very young or who have medical conditions more likely to become ill, so it is important to take a few precautions," Dr Veitch said.
"If people are exposed to too much heat they can have a range of illnesses ranging from cramps all the way through to heatstroke.
"People may be sweating a lot, but they may also get to a stage where they're dehydrated and don't sweat."
Southern Tasmanians are being warned to stay hydrated, and have a plan.
Health authorities also repeated warnings about children and pets left in cars.
The hot weather is not just confined to the state's south.
The weather bureau is expecting the temperature to hit 27 degrees until Monday in Launceston.ABC