Box scores tell you how a baseball team has done. Stock listings tell you how a stock has performed. But I’ve never seen a mechanism indicating whether weathermen have any idea what they’re talking about. Does anyone keep track of how accurate they are? —Steven Goldberg, via e-mail
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As you’d imagine, advances in weather prediction closely follow advances in technology and communications. Early forecasters had to make their best guesses using only basic gear (thermometer, barometer, etc) and personal experience with local conditions. In 1743 Benjamin Franklin (who else?) compiled reports from colonial postmasters to track a hurricane’s progress up the eastern seaboard. By 1848 weather dispatches were traveling via telegraph, and in 1871 the newly founded U.S. Weather Bureau started publishing the first general forecasts three times a day. Weather balloons carrying radiosondes went up in the 1930s, providing a look at doings in the upper atmosphere. Finally, mathematical weather-system models, first proposed in the early 1900s, came into their own circa midcentury, when (a) computers got powerful enough to handle the calculations needed to simulate atmospheric movement and (b) radar and weather satellites greatly increased the available data.
And as computer models get updated (to include things like ocean and land effects and chaos theory) and more weather stations get sampled, forecasts do, in fact, get better. According to the American Meteorological Society, sea-level pressure forecast accuracy doubled between 1977 and 1987, and by 1991 a five-day weather forecast was as good as a three-day forecast from 1981. One study of extended forecasts from 1997 to 2004 found that using a new projection system improved temperature predictions by as much as half a degree Fahrenheit, while four-day rain forecasts improved by as much as 8 percent.
Art accompanying story in printed newspaper (not available in this archive): illustration by Slug Signorino.
