Wacky Weather

Wacky Weather

March 27th, 2014 by Tim Omarzu in Fyi2014

Steam from a rooftop air unit clouds this view of the famous Dome Building in downtown Chattanooga as a burst of late afternoon snow covers the north side of the gold cap.

Steam from a rooftop air unit clouds this...

Photo by Tim Barber /Times Free Press.

Chattanooga Annual Averages

Precipitation: 52.48 inches

Days with 0.01 inches or more of precipitation: 119.6

Snowfall: 3.9 inches

Days with 1 inch or more of snowfall: 1

Days with thunderstorms: 54.8

Days at or above 90: 47.7

Days with dense fog: 27.3

Days at or below 32: 58.3

Average first freeze: Nov. 4

Average last freeze: April 1

Average first frost: Oct. 20

Average last frost: April 14

Source: National Weather Service, Morristown, Tenn.

Chattanooga Record Temperatures

Highest temperature: 107 F (June 30 and July 1, 2012)

Lowest temperature: -10 F (Jan. 21, 1985, Jan. 31, 1966, Feb. 13, 1899)

Most rain in 24 hours: 9.5 inches (Sept. 5-6, 2011)

Most rain in one month: 16.32 inches (March 1980)

Most rain in one year: 73.70 inches (1994)

Most snow in 24 hours: 20 inches (March 12-13, 1993)

Most snow in one season: 23.9 inches (1894-95)

Most snow on Christmas: 5.1 inches (1969)

Source: National Weather Service, Morristown, Tenn.

Chattanooga has all four seasons -- sometimes in the space of a week.

Take January 2013, for example. It was about 7 degrees colder than average, and even dipped into the single digits midweek early in the month. Then, a few days later, residents shed their coats and welcomed temperatures in the 60s.

Weather forecasters are loathe to use the word weird, though, to describe Chattanooga's climate.

"It's weather," said Derek Eisentrout, of the National Weather Service's Morristown, Tenn., office that does Chattanooga's forecasting. "Normal" in the weather world is based on 30-year averages of data, he said.

"You have a lot of ups and downs and ebbs and flows in 30 years," Eisentrout said.

And on average, Chattanooga's weather has some predictable patterns.

For example, the 52.48 inches of annual precipitation is split fairly evenly among the 12 months, ranging between a little more than 3 inches in October, the driest month, and close to 5 inches in January, the wettest.

That 52.48 inches of precipitation, by the way, is significantly more than Seattle's annual of 38 inches and the national average of 38.67 inches of annual precipitation.

One of Chattanooga's nicknames is "Gateway to the Deep South," and its summers can be hot, with temperatures topping 90 degrees about 48 days each year, or 13 percent of the time. Chattanooga's annual average temperature is 57.2 degrees, above the national average of 54.5 degrees.

Year-round humidity here is 75.32 percent, slightly below the national average of 77.52 percent.

While those averages may sound, well, average, the Scenic City still sees its shares of climactic ups and downs, leading to the old saying here, "If you don't like the weather, wait an hour or two and it will change."

Contact staff writer Tim Omarzu at tomarzu@timesfreepress.com or 423-757-6651.