MetService is forecasting snow down to sea level across the South Island this week, with a polar blast expected to hit the country.
Temperatures are forecast to drop on Wednesday with Christchurch in for chilly lows of -1C.
MetService meteorologist Heath Gullery says the last time Christchurch saw an October snowfall was in 1969.
In the Dunedin region, tomorrow would start with possible morning frosts, but as the northerlies changed southwesterly, showers would develop and turn to snow in the evening.
The snow was expected to lower to about 400m in the Dunedin and Southland areas, and 300m in inland Otago.
The weather was expected to clear on Thursday.
MetService said it was a "significant weather event" for October and urged farmers to be prepared for the polar blast which may bring stress to livestock.
Alpine roads
MetService says snow is forecast for some alpine roads on Tuesday and Wednesday.
Milford Road (State Highway 94)
From 6pm to 10pm on Tuesday: Snow may affect higher parts of the road for a time in the evening, and up to 1cm of snow may settle on the road above 700 metres. Snow showers may affect the road south of Lake Gunn to near sea level for a time on Wednesday, and this warning may be extended.
Crown Range Road (linking Queenstown and Wanaka)
From 8pm on Tuesday until 2am Wednesday: Snow is forecast to affect the road for a time overnight Tuesday, with 1 or 2cm possibly settling on the road above 600 metres, and lesser amounts down to lower levels. Snow flurries are possible to low-levels during Wednesday afternoon, but little if any snow is expected to settle on the road.
Lindis Pass (SH8)
From 9pm on Tuesday until 3am on Wednesday: Snow is forecast to affect the road for a time overnight Tuesday, with 1 or 2cm possibly settling on the road above 700 metres, and lesser amounts down to 400 metres. Snow flurries are possible to low-levels during Wednesday afternoon, but little if any snow is expected to settle on the road.
Arthur's Pass (SH73)
From 2am until 6am on Wednesday: A brief period of snow is possible in the early hours of Wednesday morning, and 1 to 3cm of snow may settle on the road during this time.
Porters Pass (SH73)
From 3am until 7am on Wednesday: A brief burst of heavy snow is possible in the early hours of Wednesday morning, and 3 to 6cm of snow may settle on the road during this time.
-NZ Herald and ODT
