Snow has been forecast to 500m across Otago tomorrow and sleety showers are forecast for lower-lying areas.
MetService meteorologist Emma Blades said temperatures would drop to below freezing in parts of Central Otago.
Dunedin was expected to be in single digits.
Snow was also forecast to 800m in some areas today, she said.
Heavy rain that pelted Dunedin city yesterday did not cause too many problems.
Minor slips were reported on Portobello Rd and surface flooding in some places.
Dunedin City Council roading maintenance engineer Peter Standring said contractors were working in and monitoring Portobello Rd, and Kaikorai and Northeast Valleys yesterday and in the following days in the event of larger slips.
Dunedin recorded 26.4mm of rain in the 12 hours to 2pm yesterday while Swampy Summit recorded 61mm.
For today, there will be a mix of sunshine and showers across the country, with a risk of heavy rain and thunderstorms in parts of the North Island tonight.
Auckland will get occasional showers throughout the day, with westerly winds and a high of 17C.
There is an overnight high of 11C forecast in the City of Sails and heavy showers are expected later in the day and through to tonight.
Hamilton, Taupo and around the Waikato are in for occasional showers and fine breaks; while those in New Plymouth and Palmerston North will also see similar conditions -- with temperature highs around the mid-teens.
Things look much brighter in and around Tauranga, Gisborne and Rotorua, where there are sunny spells forecast today and a temperature high of 18C in Whangarei, which will, however, see some showers at some point today.
Emergency services around the country did not report any major weather-related incidents overnight.
A spokesman for MetService said although there had been surface flooding in some parts of the country over the weekend -- including in Timaru -- there had been no major weather incidents last night.
In the South Island, Nelson, Blenheim, Christchurch, Ashburton and Timaru are all forecast to be mainly fine today.
Christchurch is forecast to have a temperature high of 11C with a chilly 5C high overnight.
Invercargill and Dunedin are in for cloudy days and periods of showers.
Cold southwesterly winds are also expected and those in Invercargill will be in for a cold night, with an overnight high of 3C.
MetService says a risk of thunderstorms is set to increase later tonight for Taranaki and the west coast areas from Waitomo to Auckland.
A spokesman said if thunderstorms do arrive, people can also expect to see heavy rain -- and possibly hail -- in these areas late
