The forecaster says the wind arrows in the video are colour-coded to the temperature as its predicts Tuesday will be "very cold" for the time of year.
A road snowfall warning is in place for the Dunedin to Waitati Highway from 8pm tonight.
Snow is expected overnight with 1cm to 2 cm possibly accumulating about the summit of the road.
MetService meteorologist Alwyn Bakker said it was possible snow would fall to 300m tomorrow morning.
"It’s going to be pretty damn cold down there. It’s going to be the coldest day of the run, with a high of just 7°C.
"This is your best chance of seeing snow in Dunedin this year."
A disturbed, strong and cold southwest flow was expected to spread over the entire South Island tomorrow, then ease later in the day.
Snow was expected to low levels, possibly sea level in some places, over the South Island at first, and it was possible warning amounts of snow above 400m could fall from Southland through to south Marlborough.
Road snow warnings
Dunedin to Waitati Highway (SH1)
Valid: 13 hours from 8pm today to 9am tomorrow
Forecast: Snow expected overnight. 1 to 2 cm possibly accumulating about the summit of the road.
Lindis Pass (SH8)
Valid: 7 hours from 9pm today to 4am tomorrow
Forecast: 1 to 2 cm may accumulate above 500 metres with lesser amounts lower down.
Crown Range Road
Valid: 17 hours from 7pm today to noon tomorrow
Forecast: Expect 4 to 6 cm of snow to accumulate above 500 metres, with lesser amounts lower down.
Haast Pass (SH6)
Valid: 8 hours from 7pm today to 3am tomorrow
Forecast: A period of snow tonight. Up to 1 cm may settle about the road above 400 metres.
Milford Road (SH94)
Valid: 20 hours from 4pm today to noon tomorrow
Forecast: Snow expected to develop about the road 5 to 10 cm of snow may accumulate above 500 metres, with lesser amounts lower down.
