It Really Is Cooler in the Shade

Waverly, IA (August 26, 2010)- Pretty much everyone agrees that it feels cooler under a shade tree than it does standing out in the open sun. A recent temperature measuring activity sponsored by Iowa-based Trees Forever shows just how accurate those feelings really are.

Attendees at the recent Bremer County Fair were invited to participate in an activity designed to compare the actual temperatures of shaded and unshaded surfaces. Around 20 volunteers – many of them 4-H youth – took temperature readings in multiple locations around the fairgrounds. Additional readings were taken around the town of Waverly.
To obtain the temperature readings, the volunteers used handheld digital laser thermometers provided by Trees Forever. They compared the temperatures of shaded versus unshaded surfaces, such as sidewalks, parking lots and grassy lawn areas.
“The most dramatic temperature difference came from a reading taken by volunteers on top of a picnic table near a food vendor at the fair,” noted Meredith Borchardt, Trees Forever program manager. “The tabletop was a scorching 144 degrees in the sun, but only 89 degrees on the shaded part. That’s a whopping 55 degree temperature difference!”
Other sun to shade temperature variances ranged from a 14 degree difference on a lawn area to a 35 degree difference on a parking lot. The average difference between shaded and unshaded surfaces was 27.5 degrees.
The Bremer County Fair temperature measuring activity was done in conjunction with Trees Forever’s new Project trEE-O2, a pilot program focused on the energy conservation and carbon sequestration benefits of trees. The program is funded in part by grants from the Iowa Power Fund and State Energy Program/ARRA funds. Waverly Light & Power also supports the project locally.
The results of this survey closely mirrored those of another temperature measuring activity Trees Forever volunteers did in Des Moines in 2007. It is interesting to note that, in both studies, the temperature readings on grassy lawns were typically 5 to 15 degrees lower, overall, than nearby paved surfaces. This emphasizes the cooling benefits of live vegetation compared to hardscape surfaces or built structures.
Trees Forever, a nonprofit environmental organization based in Marion, Iowa, has been promoting the energy-saving benefits of trees and native plants for the past 21 years. A broader 2007 study of street trees undertaken by Trees Forever in Cedar Rapids, Iowa, also highlighted and valued numerous other benefits of public and private trees, including reduced CO2 levels, improved air quality, reductions in storm water runoff, and increased property values.
So the next time you’re enjoying a cool, relaxing summer afternoon under a big shade tree, just think how much hotter you would be if that tree wasn’t there. Trees really are a practical way to stay cool!
For more information on Trees Forever’s Project trEE-O2, or the temperature measuring studies, please contact Meredith Borchardt, Program Manager with Trees Forever, at 641-430-3854, or e-mail

Related Resources:

It Really IS Cooler in the Shade
Off-Season Projects for Tree Planters