NIWAWeather keys

The colours behind your town or city forecast

The colour gradient you see behind your town or city forecast depicts the amount of cloud cover expected during daylight hours - ranging from clear blue to dark grey (overcast).

The colours are supported by weather data, made visible by hovering your mouse (or tapping and dragging) on the screen to reveal hourly (first 24 hours) or three-hourly forecasts. On iPhones, forecast data for the current hour (or three hours) will automatically appear on screen. Swipe to see later forecasts.

Temperature data

Temperatures are in degrees Celsius. The daily forecast summaries at the bottom of your screen show the expected maximum (bold) and minimum (unbold) temperatures for the day.

Wind data

Wind forecasts show the average wind speed expected (in kilometres per hour (kph)) alongside a wind direction indicator. The indicator includes the compass direction from which the wind is coming (e.g., SW for a southwesterly wind) and a pointer showing where the air is going.

What the wind speeds mean:

0 – 14kph:           Light winds – great for a walk, a barbecue or to read the newspaper outside.
15 – 29kph:         Moderate breeze – enough to fly a kite or get the washing dry without wrapping it around the line.
30 – 39kph:         Fresh breeze – time to get the windsurfer out, but maybe put the al fresco dining on hold.
40 – 59kph:         Strong breeze – use a longer club on upwind golf holes. Think about securing small loose objects like pot plants.
60 – 89kph:         Gale. Not pleasant to be outside. Small tree limbs and other debris may be flying around. Travel may be affected.
> 89kph:             Potentially dangerous weather.

Rain data

Rain forecasts are in millimetres (mm) within each hour.

What the rain rates mean:
0.1 – 2.0mm per hour:     Light rain. An annoyance if you’ve got outdoor activities planned.
2.1 – 6.0mm per hour:     Moderate rain. A miserable wet day. That’s probably the end of the cricket.
6.1 – 25mm per hour:      Heavy rain. Travel may be affected. If it keeps up, streams and rivers may rise quickly.
> 25mm per hour:           Potentially dangerous weather.

About NIWA

NiwaWeather Logo - Hovering Clouds

NIWA is the National Institute of Water and Atmospheric Research. We’re New Zealand’s leading supplier of atmospheric, freshwater, environmental and marine science services. We collect, store and manage data on New Zealand’s weather, climate, marine and freshwater resources and other important environmental parameters. We deliver that data via a range of tools and services that help Kiwis manage their interactions with the environment and its resources more productively and sustainably.

Our science also helps New Zealand communities build resilience to a range of climate- and weather-related hazards – in the face of future climate variability and change.

We’re a Crown Research Institute (CRI), which means some of our revenue comes from the Government so we can conduct research that’s in the best interests of all New Zealanders, and some is earned from the commercial work we undertake for organisations in a range of different sectors.

Our expertise and capabilities in the fields of weather and climate are significant, resulting from years of research, strong international partnerships, an extensive network of weather and climate stations and the computational power of our IBM p575 POWER 6 supercomputer – one of the most powerful of its kind in the Southern Hemisphere. This means we’re well positioned to expand our weather forecasting services to serve New Zealanders with a variety of different interests and occupations – and therefore a variety of different reasons to be looking out for their window of weather opportunity. Watch this space!

You can find out more about our structure and work by visiting our website.



Meet FitzRoy

He’s the 18-tonne brain behind NIWAWeather’s forecasts. His real name is IBM p575 POWER6, but he prefers FitzRoy – or just ‘supercomputer’ if he’s in one of his moods.

He’s a fussy individual. He occupies a specially constructed, climate-controlled (appropriately!) room at NIWA in Wellington. But we don’t mind, because he works tirelessly, 24/7, with the computational effort of about 7000 laptops. And his outputs are vitally important to all New Zealanders.

FitzRoy takes data from NIWA’s weather and climate station network, from networks managed by other organisations monitoring a range of environmental parameters, and from satellites, ships, weather balloons, ocean buoys and aircraft, and crunches them in ways beyond the comprehension of mere mortals like us.

At regular intervals he runs programmes, or ‘models’, that mimic highly complex environmental processes such as circulations in the atmosphere and oceans. All the while, he validates his own outputs against what’s happening now and what’s happened in the past. And then he predicts.

He produces the six days of NIWAWeather forecasts that help you find the best time to do all the important things you want to do. He also helps scientists from NIWA and many other organisations carry out vital research into the impacts of natural events such as severe weather, river flooding, ocean storm-surge and wave patterns. He’s even able to create scenarios of what those events and their impacts may be well into the future, as our climate changes. Our scientists then work with local authorities and other parties to ensure our communities are prepared.

So we think FitzRoy’s entitled to feel a little self-important!

Why FitzRoy? He’s named after Robert FitzRoy, a 19th century scientist, surveyor and hydrographer. FitzRoy captained the Beagle on Charles Darwin’s famous 1831 voyage. He founded the forerunner to the UK Met Office in 1854, was the second Governor of New Zealand from 1843, and was the first person to collect weather data and produce a ‘weather forecast’.

You can find out more about FitzRoy (the supercomputer) here.

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