The weather bureau's report for January has found a heatwave, months of low rainfall and dry storms combined to create Tasmania's worst bushfires in decades.
Several parts of Tasmania broke temperature records on January 4, the day fires began and eventually destroyed more than 200 properties.
Hobart recorded its hottest-ever day at 41.8 degrees, second only to Scamander's 42 degree day in January 2009.
The bureau says dry thunderstorms and a cold front off the west coast created lightning strikes.
Climatologist Lorien Martin says fires were fuelled by dry bushland created by last year's low rainfall.
"[There was] well below average rainfall in the last few months of 2012, so vegetation and soil moisture levels had dried right out," she said.
The cold front in early January helped fan the flames.
"Before that cold front came through we had a few thunderstorms around on the 3rd," she said.
"We had dry thunderstorms, I suppose, so they didn't deliver a lot of rain but there was some lightning.
"So several of those fires were started with dry thunderstorms and then when we got warm hot and windy on the 4th, the fires that had started flared in those conditions."
The efforts of fire fighters were also hampered by well below average rainfall.
© ABC 2013
13:25 EDT After a fairly cloudy morning, Sydney's skies are clearing nicely for a starry but cool night for Carols at the Domain.