Bay of Plenty residents are being urged to keep the winter woollies handy, with a series of cold southerly changes set to bring lower temperatures.

In a media release, MetService says a steady stream of cold southwesterly winds will dominate New Zealand’s weather this week, with three separate cold changes forecast to move across the country before widespread frosts develop on Thursday morning.

The first change was expected to arrive overnight on Monday, following a relatively mild start to the week under warm northwesterly winds and settled conditions.

MetService meteorologist Clare O’Connor said the shift would be noticeable.

“Temperatures are expected to drop sharply as northwesterly winds turn southwesterly,” she said.

Overnight lows of 4C and 5C are expected on Wednesday and Thursday nights.

While snow is forecast for parts of the South Island, Bay of Plenty residents can expect cooler temperatures and brisk winds as the colder air spreads north.

Further cold air arriving on Tuesday and into Wednesday will reinforce the chilly conditions nationwide.

The second front is forecast to bring thunderstorms, hail and strong winds to parts of the South Island, while snow levels could fall as low as 300m in Southland and Central Otago overnight into Wednesday.

For the Bay of Plenty, conditions are expected to remain comparatively settled, although showers may affect eastern coastal areas on Wednesday.

The coldest weather is likely to be felt on Thursday morning, when widespread frosts are forecast across many parts of the country.

The cold snap comes as New Zealand marks the spring equinox at midday on Wednesday, signalling the halfway point between the winter and summer solstices.

“Midday Wednesday also marks the spring equinox, reminding us that we are slowly but surely making our way towards summer,” O’Connor said.

“It’s good to keep that in mind on Thursday morning as we once again layer up to brace ourselves against widespread frosty conditions. While summer is coming, spring is still just getting started.”

Motorists travelling through alpine areas of the South Island have been advised to keep up to date with conditions, with Road Snowfall Warnings issued for Milford Rd, Lindis Pass and Porters Pass from Tuesday.

For Bay of Plenty residents, the message is simpler: enjoy the sunshine while it lasts and prepare for a much colder few days ahead.