Your mum has probably said it to you, but what is the truth behind the phrase?

It’s a question meteorologist get asked all the time during the cold winter months – "can it ever be too cold to snow"?

The short answer is no.

Snow can fall at incredibly low temperatures, the real question is ‘is it too dry to snow?’

Warmer air holds more moisture so colder air holds less moisture.

For it to snow a few things have to come into play, rather than just rain and cold air.

The ingredients for snow

1. A temperature profile that allows snow to reach the surface

2. Saturated air

3. Enough lifting of that saturated air to allow snow to develop aloft and fall to reach the surface

So where does the phrase come from?

The phrase, according to accuweather, probably originated as a misapplication of the relationship between temperature and the maximum amount of water vapor that can be in the air. Basically we misunderstood the scientific phrase.

When temperature decreases, the maximum capacity of water vapor that can be in the air decreases, therefore, the colder it gets the less water vapor there will be in the air.

Most heavy snowfalls happen with relatively warm air temperatures near the ground – usually at 15 degrees F/-9.44444 C or above. When the temperature drops into the single digits, or below zero, heavy snow is unlikely.

It’s not because it’s too cold, but because its too dry .

When temperatures are that low, the air’s capacity for water vapor becomes very small. No water, no snow.

The only time snow is impossible is when we reach absolute zero.

…and snow isn’t really white either

Yes, you read that right. Snow isn’t white it’s actually transparent. Snowflakes are basically just crystals stuck together.

It reflects all the colours – as it doesn’t absorb, transmit or scatter any single wavelength more than any other. The ‘colour’ of all these wavelengths is white.

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Travel advice in winter

  • Top tips for safer driving
  • How to de-ice without chemicals
  • Are winter tyres worth it?
  • Are you breaking the law when de-icing?
  • Driving in the snow could break the law
  • Check flight status
  • What to do if trains are cancelled
  • Is car insurance valid?

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