Weather forecasts facing storm of criticism
Been left out in the rain by weather forecasts in Denmark so far this summer? Don’t blame the meteorologists at national weather service DMI. They say that despite coming in last place in a recent ranking by a Swedish newspaper, they are just as good as other Nordic weather services.
Dagens Nyheter compared DMI and four other Nordic weather websites, together with weather.com, and concluded that the Danes were correct only 36 percent of the time. That put them below the group average (46 percent) and well behind the competition’s winner, SMHI of Sweden (56 percent).
The competition involved comparing the six services’ forecasts for 19 Swedish cities over a 40-day period, and, according to Niels Hansen, a DMI spokesperson, doing it that way essentially compared apples and oranges, and not the accuracy of the forecasts.
“What it did was to assign numbers to our weather symbols and then compared them with the same symbol the other services use,” Hansen said.
The problem, according to Hansen, is that different symbols mean different things in different countries. While an icon of a sun obviously means it will be sunny, what about a symbol with a sun, a cloud and two rain drops? In Denmark that means ‘sun and light rain’, but what DMI considers ‘light rain’ isn’t necessarily the same as what Norway’s YR does.
When Dagens Nyheter tried to assess whether the forecasts were correct, it compared them wtih its own symbol for the weather on the given day, which may have been different from the one the weather services used.
“That gave them different results from what they should have come up with,” Hansen said, adding that DMI does its own comparison of how accurate it is compared with the Swedish and Norwegian weather services.
“Our rate in June was extremely good,” he said. “We are absolutely sure we are just as good.” According to DMI itself, when it comes to Danish weather, its accuracy in 2011 was 95 percent, which is a ten percent improvement since 2001, although Hansen did point out that some years are easier than others to forecast.
He explained that what’s really wrong this year isn’t the forecasting, it’s the weather itself.
With the worst start to the summer in 25 years, people are looking for a scapegoat. “They can’t do anything about it and you can’t blame the weather,” he said. Instead, they blame the forecast – and the forecaster.
But while DMI said its predictions are accurate, theme parks are especially annoyed with meteorologists’ performance this summer. Form them, a wrong weather forecast isn’t just a case of bringing an umbrella and having it turn out to be sunny. It’s a matter of money.
“When they predict bad weather you can really feel the effect it has on the numbers of guests we get,” Søren Kragelund, the president of FFD, the national association of theme parks, said. “The media wants more drama because they want a good story. Everyone wants to read about the weather, especially if it’s dramatic. But the weather forecasters are the ones who come up with the story.”
Spooked possibly by an increasing number of torrential downpours in recent years, meteorologists and the media this year have been quick to warn of possible torrential rain a few times during the summer.
Most of those downpours never materialised, and that has had an effect both on how much people trust forecasts, as well as on tourism, especially when it has to do with outdoor activities, Jens Zimmer Christensen, the chairman of Horesta, the national interest organisation for the hospitality industry, explained.
“Naturally, bad weather can mean that people who are staying in summer houses and camping grounds are less likely to return or recommend it if the weather has disappointed them,” he said.
But even though he too noted that weather forecasts competed against each other for the most viewers, he recognised that meteorology is not an exact science.
“Our weather is changing and there are unusual patterns all over the world, which makes it even more difficult to be accurate. People should bear that in mind before they criticise weather forecasters too much.”
Following the study, DMI asked Dagens Nyheter to disclose its data with an explanation of how the assessment took place, so that it can see if its meteorologists can improve their forecasts.