Bitterly cold weather has been gripping Tasmania as temperatures plummet as much as eight below average.

Widespread frost has affected much of the state in the last few mornings and has been severe in central and eastern parts. Liawenee has had minimum temperatures of minus seven degrees in the last two days, six degrees below average.

Some valley locations, such as Bushy Park and Ouse, which dipped to minus four on Wednesday morning, failed to get within seven degrees of the average maximum. Bushy Park only reached three degrees and Ouse four. Fog and a lack of wind were the main culprits, hampering any warmth from the sun. For Bushy park this is likely to be its coldest day in more than two years and coldest July day in at least eight years.

Sub-freezing temperatures will again be a feature over susceptible parts of the state on Wednesday night and Thursday morning with help from light winds. This will lead to the formation of ice and fog.

A Road Weather Alert has been issued.

The next few nights will be warmer with help from extra cloud and wind.