New Zealanders will get a "shock to the system" this week as temperatures drop around the country.
Much of central and southern New Zealand was on some form of weather watch or warning because of a low-pressure system making its way up the South Island, MetService meteorologist Andrew James said.
It brings with it heavy rain in the west and strong north-westerly winds.
Heavy rain warnings are in place for Buller, Westland and the Canterbury lakes and rivers headwaters, and a strong wind warning is in place for Canterbury high country, with expected gusts up to 120km/h in exposed places.
Strong wind watches are in place for Otago, inland Southland and Clutha from Monday afternoon. Coastal Southland and Clutha were already feeling the wind on Monday morning.
Road snowfall warnings are in place for Tuesday morning on Lindis Pass, Haast Pass, Crown Range Rd and Arthurs Pass.
It was expected to fall as low as 600m on some of those roads.
On Milford Rd between 6cm and 12cm could settle on the road near Homer Tunnel between 11pm tonight and 3pm tomorrow.
Lesser amounts were expected to settle to 500m.
While it's all rain and bluster for those parts of the country, the north-westerly winds "tend to bring warming", James said.
Unfortunately, as that system moves on, temperatures in some areas are expected to plummet. Alexandra is tipped to go from a high of 17C today to just 2C overnight, with -1C and 0C the next two nights. Queenstown is expecting similar overnight temperatures this week.
Dunedin won't be quite as cold but overnight temperatures will be single digit all week.
"After the front goes through, it is cold in behind . . .it's going to be a bit of a shock to the system there," James said.
"There's a number of places where there's single-digit, close-to-zero temperatures overnight."
Despite the below-average temperatures, the weather is expected to be "more settled", with partial cloud in the west and fine weather in the east from Wednesday.
"The further north you are, the better the weather gets," James said.
The "changeable" weather - going from rainy but warm, to fine but cold - was common in spring, he said.
