It’s been a sleepy few days across New Zealand thanks mostly to high pressure in the Tasman Sea spreading across many parts of the country.

Light winds and calm conditions over the past weekend helped create frosts – for some in the North Island the heaviest so far this year, along with fog patches – which have continued on into this week in the usual places (ie, Waikato).

However this is one of Autumn’s tricks.  “Autumn is about summer weather conditions fading away and winter creeping in” says head weather analyst Philip Duncan.  “Highs across Tuesday in some eastern and northern areas of both islands will be into the low 20s, but being Autumn that means a colder more winter-like change will follow”.

Mr Duncan says daytime highs this week will be “all over the place” as northerly and southerly wind flows swap around.

Dunedin has a high of 18 degrees on Tuesday then 12 on Wednesday, back to 15 by Friday then 13 Saturday, possibly 10 on Sunday.

Wellington will go from 16 on Wednesday to 12 on Thursday, before warming up again around Friday and Saturday ahead of Sunday’s colder change.

“Generally speaking Wednesday is colder for the South Island and Thursday is chillier for most of New Zealand. Then conditions warm back up on Friday before a likely colder change moves up New Zealand starting in the south on Saturday and spreading everywhere by Sunday PM”.

The forecast for next week also looks unsettled as the Southern Ocean continues to become more active as head into the darker months of winter – however Sunday’s cold snap looks unlikely to remain in place with westerlies returning early next week.

“This weekend and next week will be much windier for the nation than the past few days have been” says Mr Duncan.

– Homepage image / File, Mt Cook / Elspeth Nicoll

– WeatherWatch.co.nz