Cool data: It's not as rainy as it seems

It's seems like clockwork this year: At 3pm, the clouds roll in, and by 4pm the skies open up. But if you think this summer's been wet, what you may actually mean is that this summer's been cool.

"What's remarkable about this summer is not the rain," says Pat Michaels, head of the State Climatology Office at UVA. "It's the lack of very hot days," he says.

The Climatology office has the data to back up this assertion.

"Rainfall has been about normal through mid-July," says Michael's colleague Jerry Stenger.

As of July 22, Charlottesville had received 23.80 inches of the wet stuff. But last year, the wettest on record? Holy soggy galoshes, at this point in the summer we'd had 41.71 inches– nearly twice this year's figure. By contrast, on July 22, 2002, at the height of the drought, a mere 16.97 inches had fallen.

And in terms of number of rainy days, Stenger says, this year we're dripping in at just slightly above average. As of July 22, we'd had 77 days of measurable precipitation compared to the average of 72 by July 22 in the past.

Michaels says some people may have the feeling we've gotten a lot of rain thanks to a preponderance of afternoon thunderstorms. Those storms, says Michaels, are caused by cooler-than-normal air "aloft," air that's 18,000 to 20,000 feet up. That, he says, means "the atmosphere is more unstable and has more tendency to form thunderstorms in the afternoon when temperatures heat up."

But despite the regular precipitation, it's actually the cooler temperatures, says Michaels, that make this year feel wetter.

"Over in the Shenandoah Valley near Fishersville, they haven't recorded a single 90 degree day," he says. Here in Charlottesville, there have been nine days above 90, but not one above 95– an anomaly in a Central Virginia July, where by this time in an average year we've had five days over 95 degrees and 18 days over 90 degrees.

Combine those low relative temps with high humidity, and you've got, well, lots of frizzy hair.

The dew point– the temperature at which dew forms, and which is used as a measure of the air's humidity– has been higher than average– in the 70s– whereas the average is somewhere in the upper 60s, says Stenger.

"When we look at all the moisture," he says, "we've been seeing maximum [temps] held down, and the minimum elevated."

So what do these cooler than normal temperatures mean? An end to global warming? Apocalyptic horsemen?

"I'm a secular climatologist," laughs Michaels. "It means people should be happy."

Jerry Stenger says it's not the rain, silly, it's the cool!