Snow in Dunedin, early July. Photo: RNZ/Tess Brunton
MetService is warning a polar blast is set to bring heavy snow to much of the South Island from Wednesday afternoon.
Heavy snow watches were in place for inland parts of Otago, Fiordland and Southland.
Watches were also issued for inland areas of Canterbury and Marlborough from Wednesday evening.
"Snow is expected to 300 metres, with heavy falls above 500 metres where accumulations may approach warning criteria," MetService said of inland Canterbury, south of Arthur's Pass to Lake Tekapo.
Marlborough residents should expect snowfall between 8pm Wednesday and 9am Thursday.
Buller and Tasman were also expected to get early morning snow, down to about 300m from 3am until 10am.
Meteorologist April Clark said snow could get as low as 200 metres for a lot of the South Island, with possible significant amounts above 400 metres.
A road snowfall warnings was issued for the Napier-Taupo Road from 3pm Thursday, with two or three centimetres expected to settle on the state highway.
Warnings were also in place for the Desert Road, Dunedin to Waitati Highway, Remutaka Hill Road, Lewis Pass, Arthur's Pass, Porters Pass, Lindis Pass, Crown Range Road and Milford Road.
Clark said motorists travelling on alpine passes should take extra care and check the conditions before setting off.
Snow was set to clear over the South Island on Thursday.