"North and east will definitely be the best places."
The West Coast of the South Island is set to have the wettest start to the year, particularly for those in Fiordland.
Adams said eastern parts of the South Island would also have scattered rain, but nothing like what was expected in the west.
Western parts of the North Island, including Wellington, Kapiti, and Taranaki, could also expect some showers.
"For those in the Cardrona Valley for Rhythm and Alps there will be some scattered rain around," Adams said.
"It may or may not actually fall on the festival site, but they'll certainly see it on the surrounding mountains.
"It should ease off overnight and give them enough time to dry out their tents in the morning before they head home."
Whatever weather you get over the new year, MetService is predicting that will stick around for a few days.
A low pressure system has stalled over the country, meaning nothing will change for a few days, except to possibly bring more rain.
Hottest spots to spend New Year's Eve
Auckland SkyCity fireworks Auckland will be welcoming 2018 with the famous Sky Tower fireworks. There will also be a free street party at SkyCity with bands including Sons of Zion and Three Houses Down. And the fun won't stop at midnight — rappers Che Fu and King Kapisi are to play their first gig of the New Year after the countdown at SkyCity. 5pm SkyCity, Auckland CBD
Coromandel Outdoor concert Benny Tipene and DJ General Lee will be among acts performing on a full outdoor stage at Williamson Park, Whangamata on New Year's Eve. Be sure to leave your booze and picnic at home – the event is alcohol free and no BYO food is allowed. There will food and drink stalls on site. Tickets from $25 6.30pm-12.30am Williamson Park, Whangamata
Gisborne Rhythm and Vines The festival regularly attracts 20,000 people, and is sold out for this year. If you were lucky enough to nab a ticket, you can enjoy your countdown with a soundtrack from local artists include P Money and Savage. Don't forget not to drink and drive - police have warned they'll be breath-testing everyone leaving the festival.
Wellington Wellington fireworks Bring in the New Year with tunes, food trucks and fireworks on the picturesque waterfront. The Julie Lamb band and Orchestra Wellington will have you singing and swaying until the fireworks start at midnight. Be sure to take the wee ones along for the kid's countdown and fireworks at 9pm. Free 8pm-12am Whairepo Lagoon by Frank Kitts Park, Wellington
Christchurch Christchurch Fireworks The Hagley Park event is family-focused from 6.30pm, including a children's countdown. After 9pm it's more of a party, with music from DJ Bailey Wesborn, Headrush, and Danger Baby. Countdown with the crowd before the fireworks at midnight. Free 6.30pm-12.30am Hagley Park North
Today's outlook for the main centres
Whangarei: Fine spells, but cloud increasing during the day. High of 26, low of 18. Auckland: Fine spells, but cloud increasing, some showers. High of 24, low of 18. Hamilton: Fine at first, but cloud increasing from afternoon. High of 24, low of 15. Tauranga: Fine, with high cloud increasing in the evening. High of 26, low of 17. New Plymouth: Cloud increasing with a few showers, mainly from afternoon. High of 21, low of 17. Wellington: Cloud increasing, with a chance of showers. High of 20, low of 16. Nelson: Cloud increasing, a few showers from afternoon.High of 22, low of 17. Greymouth: Rain, easing evening, northeasterlies. High of 19, low of 14. Christchurch: Cloud increasing, a few showers from afternoon. High of 25, low of 13. Dunedin: Occasional rain, clearing evening. High of 21, low of 12. Queenstown: Occasional rain, clearing by evening. High of 19, low of 11. Invercargill: Cloudy with occasional rain, clearing to fine in the afternoon. High of 19, low of 11.