Checking for rain: Because TV forecasters aren’t that reliablealtrendo images/Getty Images
When was the last time your weather forecaster got it this wrong?
After incorrectly predicting a sunny weekend, BBC weather people were forced to apologize on Sunday to those who were caught out in the rain.
The Telegraph reports BBC forecasters ignored computer weather models and insisted on sticking to their own predictions for hot, dry weather. Many barbecues and outings in southeast England were ruined by subsequent thundershowers.
"There are thunderstorms there which were not represented in our forecasts over the past couple of days or so," BBC weatherman Philip Avery said in an on-air mea culpa, according to the Telegraph.
"I have to say we can't even blame the computers; the computers actually wanted to put those thunderstorms in there but forecasters thought it wasn't supported by enough evidence and so we went for the dry, hot option.
"Having said that, apologies to anyone who has had their next few hours ruined."
So just how accurate are local weather forecasts?
In a 2008 blog post, Stephen J. Dubner, co-author of Freakonomics, said the answer depends on how far into the future forecasters are predicting.
"Do not plan your weekend activities based on the T.V. weather forecasts unless it is already Thursday – but waiting until Friday would be even better," he wrote.
Mr. Dubner based this conclusion on the observations of an electronics and software engineer, J.D. Eggleston, who tracked the weather forecasts of Kansas City television stations for seven months.
Mr. Eggleston found that, for seven-day forecasts, most stations' temperature predictions were accurate within 3 degrees Fahrenheit on day one. But their accuracy worsened with each day. Forecasts for the seventh day tended to be off by 6 degrees.
Most of the meteorologists he tracked merely took a "blind stab" at their seven-day forecasts and adjusted their predictions as the week went on, Mr. Eggleston said. The most inconsistent forecaster predicted a high temperature of 53 degrees for the following week, only to later change that prediction to 84 degrees – a difference of 31 degrees.
The responses Mr. Eggleston received from local meteorologists and their station managers were hardly reassuring.
"We have no idea what's going to happen [in the weather] beyond three days out," one told him.
"All that viewers care about is the next day. Accuracy is not a big deal to viewers," said another.
How much stock do you put in weather forecasts?
Wency Leung