When the islands south of New Zealand start recording temperatures of minus 1 at the warmest part of the day you know a bitterly cold southerly is on the way. 

The weather stations at Campbell and Enderby Islands act as warning shots when southerly blasts are on the way and as of 2pm the temperature had plateaud at zero on Campbell and dropped 2 degrees to -1 on Enderby.

Campbell is furthest away, about 650kms south of Bluff, whereas Enderby is only 450kms.  At a rough estimate WeatherWatch believes the coldest air is surging north at around 100km/h but will slow down as it approaches New Zealand. 

By these calculations we expect snow to start falling in Southland mid to late this evening.  It’s already close to snowing in northern Southland with strong westerlies blowing, and with winds turning southerly later today it’s not going to take much for snow to start.  As of 2pm it was 3 degrees in Gore with showers, 6 in Invercargill with winds gusting 80km/h and just 6 in Dunedin.  It was 3 on Stewart Island.

Northerlies further north are keeping conditions milder in Wellington where it’s 13, while a weak cold front in Auckland today has seen temperatures drop from about 16 to 14 this hour.

Purerua in the Bay of Islands and Gisborne share the top spot with 18 degrees followed by 17 in Kaikohe and 16 in Whangarei, Tauranga and Whakatane.