Māori weather and climate indicators – a poster from NIWA

I notice that NIWA, New Zealand’s National Institute of Water and Atmospheric Research, has a poster of Māori climate and weather indicators for download on its website. You can either grab the pdf or order a full-sized paid-for poster. This is a slice of it:

Maori Climate Poster from NIWA (part)

The weather (day-to-day state of the atmosphere, varying from minutes to weeks) predictors include:

  • From Te Roroa: The sound of breaking waves up the valley = Approaching rainfall and inclement weather is expected
  • From Te Whānau a Apanui: The plume from White Island lies to the left = Rainfall expected; The plume flattens and the end breaks off = Watch out for extreme weather

The climate (synthesis of weather, averaged over longer periods from months to years) predictors include:

  • From Te Arawa: Flowering starts on the upper branches of Pohutukawa and progresses downwards = A cold and winter-like season will follow; Flowering starts on the lower branches and progresses upwards =  A warm and pleasant season lies ahead
  • From Kai Tahu: Early and profuse flowering of Tï kouka (Cabbage) tree = A long hot summer follows

A good companion read for the poster is this piece on Te Ara, New Zealand’s encyclopedia, about Māori customs around weather and the creation stories of where wind, clouds, rain and storms come from.

The only weather predictor I remember from childhood is: Red sky at night, shepherd’s delight; red sky in the morning, shepherd’s warning, which the UK’s Met Office interprets thus:

The saying is most reliable when weather systems predominantly come from the west as they do in the UK [and New Zealand]… A red sky appears when dust and small particles are trapped in the atmosphere by high pressure. This scatters blue light and leaving only red light to give the sky its notable appearance.

A red sky at sunset means high pressure is moving in from the west so therefore the next day will usually be dry and pleasant. “Red sky in the morning, shepherds warning” means a red sky appears due to the high pressure weather system having already moved east meaning the good weather has passed, most likely making way for a wet and windy low pressure system.

I came across a lot of sites featuring old-timey weather predictors. I like this one on Farmers Almanac about dew:

When the dew is on the grass
Rain will never come to pass.
When grass is dry at morning light,
Look for rain before the night.

Why? If dew has time to form on the ground overnight, it means the night was clear without any clouds. Clear skies allow the earth to cool, and water to condense in the form of dew (or frost at cooler times of the year). If the night is cloudy, the clouds act as a heat barrier keeping the heat in and not allowing dew to form. This saying assumes that if the night skies are clear, the day following will also be cloud-free.

NIWA has a bunch of other posters for sale that depict, among other things projected rainfall, what the seabed looks like around New Zealand, undersea volcanoes, and the country’s energy assets.

Other NIWA posters

On a related note: If you’ve ever wondered how weather balloons are used in New Zealand, check out this post by Jacqui Bridges on the Met Service blog.