MetService is warning "significant" weather is on its way over the next week, after last week's bout of pleasant, sunny days.
The forecast said a complex weather system will move over the country in the next few days and bring cold and wet weather with it.
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"Most people can expect to see some rain over the next few days," said MetService meteorologist Tui McInnes. "However, snow is surprisingly the main focus of this event."
Snow this close to summer is a very rare occurrence, but not unheard of, MetService explained. Mr McInnes said the South Island will be most affected, but the central plateau may also get a light dusting.
"We could see snow to 400m in Southland and 500m in Otago and Southland," Mr McInnes said.
"There are a handful of Severe Weather Warnings and Watches in place, so this is certainly an event to stay up to date with."
There is a heavy snow warning in place for Otago, Inland Clutha and Southland from 11pm on Sunday to 6am Tuesday.
A heavy snow watch is in place for Southern Lakes, Eastern Fiordland and Inland Dunedin from early Monday morning to midday on Tuesday.
A heavy rain watch is in place for Clutha, Dunedin and North Otago from 4am on Monday to 9pm on Tuesday.
Mr McInnes also warned the weather will bring with it a risk of hail, which could prove problematic for horticultural regions.