WeatherWatch.co.nz has issued our second ever seasonal forecast in partnership with IBM and it looks as though December’s pattern will continue on into January. It’s a fairly unsettled pattern over the South Island and even the upper North Island (which often is more settled) will have a windier start to January/2020.

Highs from Australia are keeping northern NZ leaning drier while lows in the Southern Ocean continue to bring rain events and surges of cooler air into the South Island and up NZ’s western coastline. The squash zone between these highs and lows will encourage windier sou’westers which will make for cooler weather for regions hugging the Tasman Sea or southern coastal areas of both islands (around the Straits, for example).

Canterbury remains a tricky area to forecast – the region had extra rain in Decemeber which we forecast, but it doesn’t take much for Canterbury to ‘turn dry’. Some areas will get more than average rainfall – but it’s one region where the maps below may not perfectly represent the rainfall – so see the ‘Swiss Cheese Effect’ below to help make sense of it more.

In a nutshell, here are the ‘winners’ and ‘losers’ of this pattern extending on into and across January. There are signs that February and March may be drier and warmer though (see the maps below for 1 and 3 month outlooks). Our next monthly and climate/seasonal update will be at the end of January.

**PLEASE NOTE this was originally published Dec 30, 2019**

JANUARY WINNERS: 

• Many North Island farms have better chances of rain than they did in November
• Many holiday spots in the upper North Island lean both warmer and drier than average
• More rain for South Island hydro dams
• Most (but not all) of our most populated cities have average to slightly drier and warmer than average weather
• Helpful rain events for usually dry eastern parts of the South Island

JANUARY LOSERS:

• More wetter, cooler, weather for the West Coast, Southland and Otago
• Not so favourable weather for crop growers in Southland
• Not favourable for making hay on the West Coast
• Northland leans dry, continuing a pattern of drier than normal weather lately

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AVERAGE WEATHER IS JUST THAT: “Meh, it’s average as bro”

A number of regions will be having “average” weather this summer thanks to the injection of some cooler and windier airflows out of the South Ocean. This means it may actually feel colder as there will be fewer days with peak heat in some regions (mostly southern and western ones in both islands). In fact ‘average’ doesn’t mean cold – it just feels like it to us humans after a run of warmer than average days, or calm sunnier ones.

Western parts of the North Island, the lower North Island and the entire eastern side of the South Island (which is a large portion of NZ when you think about it!) has “average” weather coming up, generally speaking. Of course locally there will be variations but the general spread is for places like Auckland, Hamilton, Wellington and Christchurch to all be flirting with some hot days but also cooler, windier, ones. The end result – roughly average conditions for January plus or minus a little bit.

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THE SWISS CHEESE EFFECT:
A monthly or seasonal outlook isn’t a weather forecast – in other words, we may forecast a trend for your region (such as drier than average) yet you get some big downpours and locally you buck the trend. This is what we call the “Swiss Cheese Effect” simply because holes appear in our maps where the downpours form. The below maps are a great general guide but there are always surprises in our weather. 

This page here gives you better tips at making the most of these seasonal outlooks – and giving you further silver linings to look for, or perhaps put a better way: Understanding the Swiss Cheese Effect is a bit like reading and understanding the fine print! 

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Please note, this is only our second ever climate forecast. If you want to judge our December effort, please click here to read it, then give us feedback. 

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RAINFALL TREND OUTLOOK

JANUARY:

JANUARY, FEBRUARY, MARCH:

JANUARY:

JANUARY, FEBRUARY, MARCH:

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TEMPERATURE TRENDS:

JANUARY:

JANUARY, FEBRUARY, MARCH:

JANUARY:

JANUARY, FEBRUARY, MARCH:

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NEED MORE DATA?
Try our new website RuralWeather.co.nz – it has more freely available weather data for your location than any other website on earth (please note it takes 10 seconds to load the first time you visit).

*WeatherWatch.co.nz creates these new outlooks with our IBM partnership and are independent to tax funded forecasts from both Niwa and MetService. We encourage people to compare forecast providers and, over time, share your feedback about accuracy and communication – as we know there is definitely room to improve here in New Zealand in this space. Thanks for your incredible support and feedback!

– WeatherWatch.co.nz – Proud to be an IBM business partner.