A broad low is moving slowly away to the east of New Zealand, directing a strong cold southerly flow onto the country, which will gradually ease as the low pulls away.
In Northland and Auckland showers are expected, some heavy with possible thunderstorms this morning.
Showers will clear this morning in the Waikato, Coromandel, Bay of Plenty and Taupo areas, and there will be occasional showers and snow possible to 800m in Taranaki, Whanganui, Horowhenua and Kapiti Coast.
Gales in the Wellington and Wairarapa areas will ease.
Gisborne, Hawkes Bay and Manawatu will see cloudy periods and showers retreating to the east coast early.
And the majority of the South Island coasts will be drenched in showers for much of the morning - while inland, snow is expected down to 500m.
On Monday MetService is predicting the weather will be "mainly fine" with showers moving west across the North Island and rain and snow in places in the South by nightfall.
Police are warning motorists to take care over remainder of Queens Birthday Weekend - one of the busiest on New Zealand roads.
One person has died so far this weekend following a fleeing driver incident in South Auckland on Friday night.
Another died on a rural property yesterday after an incident involving a motorbike - but the incident will not be counted in the holiday road toll as it did not occur on a public road.
The official holiday period for Queen's Birthday Weekend began at 4pm on Friday and ends at 6am on Tuesday June 6.
Last year there were two fatal crashes and 118 injury crashes reported.
These crashes resulted in three deaths, 36 serious injuries and 122 minor injuries.
Of the deaths, two were drivers.
Of the crashes, 43 per cent involved single vehicles in which a driver lost control or ran off the road; 15 per cent were intersection collisions and 14 per cent were overtaking and or head-on collisions.
The most common driver factors contributing to crashes were losing control, alcohol, travelling too fast for the conditions, failing to give way and not seeing the other road user.
In 2017 there were four fatal and 97 reported injury crashes resulting in four deaths, 31 serious injuries and 106 minor injuries.
Police national road policing manager Superintendent Steve Greally urged drivers to "stay alert, be patient" and not to rush.
"The lives of you and your passengers are worth more than arriving a few minutes earlier," he said.
Police will be out in force this weekend, taking an "active and visible presence" on the roads - targeting high-risk driving behaviours and focusing on highways and open roads that are popular holiday journey routes.
"More than 160 people have died on our roads this year," said Greally.
"Tragically, many of those deaths could have been prevented if everyone took these four simple and proven road safety actions that prevent serious injury and death on our roads."
He had some simple safety advice for road users.
"Make sure everyone has their seatbelts on; remove distractions and stay focused on driving; don't get behind the wheel if you've been drinking or are tired; and drive at a safe speed for the conditions," he said.
"Put road safety first and make sure you, and everyone else on the road, gets to their destinations safely and unharmed.
"It takes everyone on the road to make it safe.
"Be aware of the increased number of vehicles around you, pay extra attention on open roads and in rural areas, and adjust your speed to the driving conditions."
Police have a 4km speed tolerance in place over the weekend, meaning any driver detected by a safe speed camera exceeding the area's posted speed limit by more than 4km/h will be ticketed.
"Our officers will still have discretion in how they deal with incidents and how they are enforced," said Greally.
"As always, police's focus is on preventing harm on our roads."
More tips for safe long-distance driving
• Drive with your headlights on and be seen.
• Increase following distances.
• Avoid travelling in bad weather if you can.
• If you're driving a long distance, take regular breaks and share the driving when
you can.
• Don't attempt to overtake traffic unless it's completely safe to do so – it's not worth
the risk.
• If you are towing or driving slowly, pull over regularly to let other vehicles pass.
• Plan your journey and prepare for delays.