Simon Carr: Predicting weather is a mug's game

Three days out and the forecasters are guessing – and it's been proven so

Share
Related Topics

We still fall for it and it's hard to know why we don't learn. The cold, hard truth is that weather forecasting more than three days out is a mixture of salesmanship, superstition and morbid curiosity. So I offer a bet to any professional meteorologists out there. I will bet my farm against yours that my five-day forecasts for the rest of this year will outperform yours.

That's quite a bet, considering you have a multibillion-pound budget at your disposal and a trillion terabytes of computable data. Me, I have £4.50-worth of manuals and a hangover – and I will win without trying.

An initial question: what does a 50 per cent chance of snow mean? That the last 100 times these conditions occurred it rained on 50 of them? This is meaningless – "the conditions" are never the same. Weather never repeats itself.

The weather is the biggest non-linear system we have. Tiny errors in measurements here make larger differences there, and the differences compound on other false measurements. Three days out you guys are guessing. And it's been proven you're guessing (see below).

And what about a 60 per cent chance of next summer being a "barbecue summer"? This really is rubbishy. Do you really want us to believe that you have discerned that in the last 100 years when "current conditions" occurred, 60 of them resulted in long, hot summers?

I say, then, with sublime confidence, that by using seasonal averages, and the naïve forecast that tomorrow will be much like today – my forecasts will outperform any professional's.

The Freakonomics people looked at TV weather forecasts in Kansas and found that the predictions of rain the next day were correct 85 per cent of the time. That sounds impressive until you ask the trick question. How often are you right if you NEVER predict rain? Then you are correct 86.3 per cent of the time. If you exclude settled periods (long, dry summer periods), the success rate drops off – in some cases to zero.

That zero, incidentally, was scored by the National Oceanic and Atmospheric Administration, despite its $4bn budget.

This uncertainty should be taught in schools. It would unsettle all sorts of grandiose pronouncements, schemes, plans and political projects. Global warming, for instance. As we know, sceptics say that our previous weather anxiety in the 1970s was for an ice age. But the reason for that has been forgotten.

It was argued that the climate was warming, the ice caps were melting, the cold water released into the oceans would bring down temperatures with a crash and the ice would return to Europe. And who's to say that global warming won't turn out like that?

I would make one real prediction: if the ice comes, it won't take 2,000 years. When complex systems change from one shape to another they don't do it gradually. They hold their shape until stressed too far and then they flip. If it happened, it would happen fast. In a decade. Maybe in a year. Yes, there's an 80 per cent chance of it.

React Now

iJobs Job Widget
iJobs General

VP - Group Compliance - Retail Bank

competitive: Real Staffing: VP - Group Compliance - Retail Bank A global banki...

Compliance Training Officer - Investment Bank

£60000 - £75000 per annum + highly competitive package: Real Staffing: A leadi...

Head Of Compliance Policy - Global Bank

MARKET RATE: Real Staffing: A Global Banking organisation has some exciting gr...

Business Studies Teacher

£21084 - £31868 per annum: Randstad Education Chelmsford: We are looking for a...

Day In a Page

Read Next
 

i Editor's Letter: Only a game? Far from it

Oliver Duff Oliver Duff
Abu Bakr al-Baghdadi speaking at the Grand Mosque in Mosul  

The al-Baghdadi doctrine: leading British Muslims offer their response

Independent Voices
The true Gaza back-story that the Israelis aren’t telling this week

The true Gaza back-story that the Israelis aren’t telling this week

A future Palestine state will have no borders and be an enclave within Israel, surrounded on all sides by Israeli-held territory, says Robert Fisk
A History of the First World War in 100 Moments: The German people demand an end to the fighting

A History of the First World War in 100 Moments

The German people demand an end to the fighting
New play by Oscar Wilde's grandson reveals what the Irish wit said at his trials

New play reveals what Oscar Wilde said at trials

For a century, what Wilde actually said at his trials was a mystery. But the recent discovery of shorthand notes changed that. Now his grandson Merlin Holland has turned them into a play
Can scientists save the world's sea life from

Can scientists save our sea life?

By the end of the century, the only living things left in our oceans could be plankton and jellyfish. Alex Renton meets the scientists who are trying to turn the tide
Richard III, Trafalgar Studios, review: Martin Freeman gives highly intelligent performance

Richard III review

Martin Freeman’s psychotic monarch is big on mockery but wanting in malice
Hollywood targets Asian audiences as US films enjoy record-breaking run at Chinese box office

Hollywood targets Asian audiences

The world's second biggest movie market is fast becoming the Hollywood studios' most crucial
Grindr founder Joel Simkhai: 'I've found love on my dating app - and my mum keeps trying to hook me up!'

Grindr founder Joel Simkhai: 'I've found love on my dating app'

Five years on from its launch and Grindr is the world's most popular dating app for gay men. Its founder Joel Simkhai answers his critics, describes his isolation as a child
Autocorrect has its uses but it can go rogue with embarrassing results - so is it time to ditch it?

Is it time to ditch autocorrect?

Matthew J X Malady persuaded friends to message manually instead, but failed to factor in fat fingers and drunk texting
10 best girls' summer dresses

Frock chick: 10 best girls' summer dresses

Get them ready for the holidays with these cool and pretty options 
Westminster’s dark secret: Adultery, homosexuality, sadomasochism and abuse of children were all seemingly lumped together

Westminster’s dark secret

Adultery, homosexuality, sadomasochism and abuse of children were all seemingly lumped together
A History of the First World War in 100 Moments: Dulce et decorum est - a life cut short for a poet whose work achieved immortality

A History of the First World War in 100 Moments

Dulce et decorum est: a life cut short for a poet whose work achieved immortality
Google tells popular music website to censor album cover art in 'sexually explicit content' ban

Naked censorship?

The strange case of Google, the music website and the nudity take-down requests
Howzat! 8 best cricket bats

Howzat! 8 best cricket bats

As England take on India at Trent Bridge, here is our pick of the high-performing bats to help you up your run-count this summer 
Brazil vs Germany World Cup 2014 comment: David Luiz falls from leader figure to symbol of national humiliation

David Luiz falls from leader figure to symbol of national humiliation

Captain appears to give up as shocking 7-1 World Cup semi-final defeat threatens ramifications in Brazil