The first grunty southerly of the year is coming our way, but not before days of windy warm westerlies and West Coast rain. 

This week kicks off with more of the same – warmer than average by day in almost every part of the country. This is for Monday and Tuesday due to both sub-tropical northerly and Australian westerly airflows crossing New Zealand. By Wednesday the sub-tropical portion ends but the windy westerlies ramp up further with gale force nor’westers around the upper South Island and Cook Strait/Wellington area.

It’s warmer than average by day in most places right up until the end of Thursday when the southerly change starts to move in to the lower South Island and spreads nationwide by Friday, across the weekend and again surges back up the country next Monday and Tuesday too.

Daytime highs will drop significantly by Friday nationwide across New Zealand.

Single digit daytime highs are forecast for Southland and Otago by Friday and Saturday with snow possibly falling in Queenstown on Friday and Saturday. Daytime highs in Queenstown by then will be just 3 or 4 degrees above freezing at the warmest point of the day. State Highways are likely to be impacted by snow along with all alpine passes.

But moisture doesn’t affect everyone, even with the temperature drop. This week regions like Canterbury and Hawke’s Bay will have plenty of sun and plenty of days well above normal temperaturewise, due to the west to north west winds. Daytime highs in the late teens and early 20s – well above normal for the last week of May – will be common theme all week. But be prepared for the southerly change on Friday or this weekend when daytime highs tumble by around 10 degrees.

Even northern NZ is affected by the cold change late week – although most of this week isn’t too dramatic. In fact high pressure will keep Auckland and other northern regions fairly calm this week with rain expected on Tuesday then again on Friday. Most of the windy weather will be over the South Island and lower North Island, so calm conditions prevail this week in the north. However Friday, Saturday and Sunday look more wintry in the north with windier sou’westers kicking in by Saturday and lasting until mid next week.

All of New Zealand will be colder by this Saturday – the first day of winter on the meteorological calendar.

Both Saturday and Sunday are the main days the southerly peaks across New Zealand with another surge of cold wintry southerlies early next week too, for Monday and Tuesday.  

Frosty high pressure may return to NZ around mid to late next week.

TOTAL FORECAST RAINFALL BETWEEN 5AM MONDAY AND 5AM THURSDAY:

TOTAL FORECAST RAINFALL BETWEEN 5AM MONDAY AND 5AM THURSDAY – FOCUS ON SOUTH ISLAND:

– WeatherWatch.co.nz