Coldest week of 2019? Winter freeze kicks in

Winter is well and truly here.

Much of the country woke to frosty temperatures on Monday morning thanks to a southwest flow blanketing the land - and it's only going to get colder from here.

A ridge of high pressure will build over New Zealand on Tuesday and Wednesday, bringing settled weather but plunging the country into icy conditions.

"The combination of the colder airmass from the southwest winds, the clear skies and light winds will mean overnight temperatures will plummet midweek, with Wednesday looking particularly cold," MetService says.

Using an unorthodox ranking system of blue diamond emojis, NIWA also predicts Wednesday will be the coldest point of the week.

It also speculates this could be 2019's chilliest week yet.

Aucklanders might want to put another blanket on the bed on Tuesday night with the overnight low plummeting to just 4C.

Hamilton will enjoy clear, sunny days this week but the nights are a different story, with the temperature getting as low as 1C.

It's a similar story for Wellington, although the overnight low will be slightly more bearable at 6C.

Christchurch residents woke up to frosts on Monday morning and that frigid weather will continue into the evening with an overnight low of -1C expected.

Queenstown will see sleety rain and a high of just 8C on Monday, which could sink as low as -3C by Tuesday night.

Dunedin's in for a wet, cold day with potential thunderstorms and hail and a low of 5C.

MetService has a Heavy Snow Watch in place for the lower South Island which will last until Monday afternoon. There's also a Strong Wind Watch for Coastal Otago, with southwesterlies potentially turning to severe gales in exposed places.

Newshub.