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Make the most of Tuesday's weather as the latter part of the week will see winter tightening its icy grip, the MetService says.

Spokesman Bob McDavitt said northern and eastern areas of the North Island would have a sunny day tomorrow, followed by a period of rain on Wednesday and Thursday.

The heaviest rain was likely to be in the eastern Bay of Plenty and Gisborne area on Thursday morning.

"A very cold and squally southwesterly wind flow is forecast to move from the polar ice-shelf onto the South Island on Thursday, bringing snow to the mountains and maybe to some low levels in parts of Southland and Otago."

This polar air would also blow over the North Island on Friday and Saturday making wind chill levels drop to below freezing, he said.

Farmers had a couple of days to brace for the wintry outburst accompanying the lead-up to this year's shortest day.

On Friday, day length will be down to eight hours 35 minutes in Invercargill, nine hours two minutes in Wellington and nine hours 38 minutes in Auckland.

- NZPA