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InfoGraphic: All the details on the cold blast can be found here

A low moves over central New Zealand today pushing in from the west allowing in a very cold southwest flow from afternoon. Strong cold southwesterlies continue on Friday and Saturday.


Blue – Rain about the upper South Island eases around midday, rain about the lower North Island becoming heavy at times during this morning then easing late afternoon.

Purple – South to southwesterly winds will be strong with a chance of gales about many coastal parts of New Zealand during the day.

White – During the afternoon a very cold southwest change moves onto the lower South Island then spreads northwards into Canterbury by evening then Marlborough for a brief time overnight. It must be noted that while cold and strong this change doesn’t hang around very long. Some snow to 400m about the lower South Island, 500m about Canterbury and 600m about Marlborough as this front moves through. Areas of snow flurries may vary + or – 100m.


Purple – Strong cold southwesterly winds continue about coastal parts of the country during the day with winds likely gusting to gale at times.

White – Late afternoon a very cold southwest change moves onto the lower South Island which reaches Canterbury later in the evening / overnight then the lower North Island overnight or perhaps more towards dawn on Saturday. This change will be colder then Thursday’s bringing snow flurries about the lower South Island to low levels (50 – 100m) and perhaps to 400 or maybe even 300m about Canterbury. 400m about Marlborough overnight, 600m overnight about the ranges of Wairarapa and the Central North Island towards dawn on Saturday. Due to the nature of this particular change some parts of North Otago, South Canterbury and perhaps up into parts of Mid Canterbury may be fairly sheltered meaning little snow falling in these areas. The heaviest snow will likely be about Southland / Otago with lesser amounts further north.


Purple – Strong cold southwesterlies continue about coastal parts of New Zealand during the day, winds may gust to gale at times.

White – Snow flurries about the lower South Island to low levels (50 to 100m), 300m about Banks Peninsula and then reaching down to about 500 or perhaps even 400m for the Central North Island. Snow isn’t very heavy in theses areas (it may be persistent in the morning about the lower south however) but it is very cold and quite low. Conditions gradually ease during the day.

– Please note, the idea behind this update is to focus on the main weather highlights, which is why not all regions are mentioned. 

For specific 10 day information for your city, town, rural community or island please see the 1500 forecasts on our homepage!

– Aaron Wilkinson,


Guest on 17/05/2017 11:07pm

Hello I have a bad fear of the wind, it says gale westerly and sw for Friday , how strong might these get mean speed and gusts in rangiora area ?

WW Forecast Team on 17/05/2017 11:15pm

Hi there – the worst of the winds will be coastal and out to sea just to your east. Rangiora may get some big south to south west gusts as the main fronts move through – and Saturday sure looks cold and windy, but at this stage mean speeds look to be below gale force for your area. Keep an eye on our forecasts in case this changes – and our 10 day Rangiora forecasts have hourly wind speeds for each day (showing mean speeds).  Also, our 10 day Christchurch forecast may have more details about the general forecast (as we write more detailed forecasts for the main centres). Both the Chch and your local Rangiora forecast should give you a very good idea about what is happening.

All the best,

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