Twice a month, the Met Office boldly predicts the weather
30 days ahead from their HQ at Bracknelll, in Berkshire.
They've got 20,000 customers all eager for their news,
including farmers, builders, nationalised industries and schools.
But most of us aren't quite so eager
because we think the forecasts are never right.
But do we perhaps just remember the ones that we think are wrong?
January is likely to be colder than the seasonable average, although
one or two mild spells are likely, cold weather is expected to predominate
January 1967 in London's Hyde Park, where people bathe and picnic.
Elsewhere, roads to the coasts are packed in a sudden spell of warm weather.
December 1967, settled and mostly
dry spells may continue to be more frequent than usual.
There are also expected to be more changeable spells with rain at times.
December 1967, the South and most of the country grinds
to a halt in an unexpected and unannounced blanket of snow.
But there was no mention of it in the long range forecast. Why not?
All we try and forecast really is differences from normal.
For instance, if we mentioned snow, this means we would either
say it's going to be less frequent than normal or more frequent than normal.
Well, in December, the average number of days
of snow in southern England is about three.
So that if we were expecting roughly three days of snow this December,
we shouldn't mention it.
If we were expecting 10 days, we would have said snow more frequent than usual.
Making a long range weather forecast is a serious business.
And the weathermen don't take their responsibilities lightly.
A computer called Comet is there to help them.
The day before a forecast.
It's fed with information about the last month's weather,
and then it searches its memory for a previous month with similar conditions.
The forecasters then look at what happened in that case
and based their predictions accordingly.
Comet has access to records going back nearly 100 years.
But forecasting is still a human effort
worked out by discussion and debate.
On the day of the forecast, six weatherman
sit down to analyse the data, including the computer's output.
The computer does do the daily weather forecast, but not the long range one.
We can't in fact,
use the electronic computer in this way for several reasons.
One of the reasons is that we haven't really had sufficiently
good coverage of data over the world as a whole.
But the main reason is that in order to carry out these computations,
which would be necessary, we should need a computer,
which is about 25 times as powerful as anything presently known in the world.
And that includes America.
So that, at the moment, we're in no position to try and compute the weather.
Well, quite honestly, how accurate do you really think it is?
Twenty five per cent of our forecasts are misleading and
therefore really are basically worthless.
But of course, we do have our successes.
Seventy five percent are, I say, better than chance.
Normally the forecasts are written in a vague way, like a horoscope,
so that they can rarely be found to be completely inaccurate.
But they are, in fact, definite on two things.
Temperature and rainfall.
And here they are usually correct.
The Met men are aware of their mistakes, but they don't get much sympathy
even from their own kind.
An article here says their forecasts are little more than blind guesswork
and that any intelligent layman could do just as well.
So we tested this theory today.
Bit colder than what we've had,
not quite as much snow as we had in '47 and a fairly good spring.
I think we're in for a harder winter than usual.
My guess is a fair amount of snow.
I suppose much the same as usual December, January weather, I expect we'll have some snow
and I think it's rather unseasonably mild at present.
Well, I'd say very cold, frosty and snowy.
- If you were asked to predict the weather for the next 30 days,
what would you say it would be like?
Lousy.
It has been said that, in fact, the long range weather forecasts suggest blind
guessing and the layman, any intelligent layman, could do just as well.
- What do you say to this?
Well, of course, that's not true.
An intelligent layman might be able to do a little bit better than chance
but he wouldn't be able to beat us.