"Remember to clear your gutters and tie down any loose items outside. Here are some helpful tips below on how you can prepare for storms this winter."
Saturday is also the shortest day of the year in terms of sunlight with Invercargill to get 8.5 hours of daylight - 7 hours less than what it receives on the longest Summer day.
Once we get past the weekend, the weather should be more settled next week thanks to an "enormous Australian high pressure system", fellow forecaster WeatherWatch said.
Earlier, Kiwis across the North Island woke today to drizzling rain ahead of the weekend's cold change.
New Plymouth was the country's wettest town at 5.30am with 3.8mm falling, MetService said.
Alexandra was the coldest with a low of -2.2C at 5.30am, while Whitianga was the warmest with a low of 15.7C.
Wellington was one of the windiest spots with a 33km/h wind at Lyall Bay.
Fellow forecaster WeatherWatch said rainfall levels shouldn't be too heavy today and that most regions can expect warmer than average temperatures - apart from the Southern Alps where snow is set to fall.
But a cooler change is on its way, blowing in on Saturday and pushing temperatures down into next week.
On the plus side, many regions will see sunny skies next week, WeatherWatch said.
Aucklanders can expect occasional showers this morning before a fine afternoon and top of 17C, MetService said.
A cloudy Saturday with a top of 15C is then forecast before the rain returns on Sunday with a top of 15C as well.
Whangārei, Tauranga and Napier are all set for tops of 18C today with morning rain clearing to fine afternoons. Rainfall in Tauranga may be heavy, however.
Hamilton and New Plymouth are also set for morning showers and fine afternoons with tops of 17C and 16C.
Residents in Wellington are in for a top of 14C with a rainy morning and cloudy afternoon.
In the South Island, Christchurch and Dunedin residents can enjoy sunny days with highs of 15C and 13C.
Today's weather
Whangārei: Occasional rain, clearing to fine spells by this afternoon as winds change southwest. High 17C, Low 8C
Auckland: Cloudy, with a few showers turning to rain afternoon. Northeasterlies strengthening in the morning. High 16C, Low 12C
Hamilton: Occasional rain, clearing afternoon to fine spells. Winds turn southwest. High 17C, Low 4C
Tauranga: Rain, possibly heavy at times, clearing afternoon. High 18C, Low 6C
Rotorua: Rain, clearing in the afternoon. Northerlies changing southwest. High 15C, Low 4C
New Plymouth: Rain easing to a few showers in the morning, and clearing afternoon. High 16C, Low 5C
Napier: Rain at times, clearing in the afternoon and becoming fine. High 18C, Low 3C
Whanganui: Rain at times, clearing late morning and fine spells developing. High 17C, Low 7C
Wellington: Rain clearing by late morning, but remaining partly cloudy. High 14C, Low 8C
Nelson: Rain before dawn, then a fine day. Southwest breezes. High 15C, Low 3C
Christchurch: Fine. Northerlies. High 15C, Low 2C
Dunedin: Fine. Northerlies. High 13C, Low 4C
