It may only be 10 days to the official start of summer, but there’s snow on the way.

MetService is forecasting snow to 400 metres in Southland and Otago on Friday as a series of cold fronts sweeps across the country late in the week.

The arrival of southerlies is expected to bring plummeting temperatures.

Christchurch is forecast to reach 28C with northwesterlies on Thursday, then get no higher than 14C as winds from the south strengthened on Friday.

The air bringing the cold temperatures would be coming up from deep in the Southern Ocean, says MetService meteorologist John Law.

“The real noticeable impact will be to places on the eastern coast of the South Island, where we’ll find a big drop in temperatures.”

Southerly winds are also expected to be strong for a time around the end of the week along eastern coasts.

“There will be some snow. It will be down to low levels in the far south.”

But a high pressure is expected to build behind that. “So what we will end up with is cold but dry air.”

MetService is forecasting a mostly dry weekend across much of the country, but that doesn’t include Wellington, Wairarapa, Hawke’s Bay and Tairāwhiti, where there’s a chance of heavy rain at times from Friday through to Sunday.

The southerlies are expected to have some impact even in the north, says John.

“I think you will find even there it does cool down. Perhaps a cold night overnight Friday into Saturday, temperatures back down to 9C or 10C through parts of Auckland, but daytime highs still in the high teens.”

The MetService forecast is showing showery weather in Auckland through to Saturday, with strong southerlies on Saturday, followed by a fine day on Sunday.

Wellington is being promised a brilliant Wednesday, with sunshine, light winds and 21C. But it's downhill after that, and while Thursday is still OK, the rain and southerlies move in after that.

The predicted high on Saturday is just 13C.

Conditions are looking good in Christchurch through to Thursday evening, when the southerlies were due to arrive. Forecast daytime maximums drop to 14C on Friday and Saturday, with lows of 4C overnight Saturday and Sunday.

While temperatures will be dropping significantly in Christchurch, they’re still expected to be well above the lowest November daytime high recorded in the city.

That was on a day in 1967 when the maximum only reached about 8C.

-Michael Daly/Stuff.