TEMPE, Ariz. - This time of year, misters are on full blast. But do they actually do a good job of cooling you down and by how much?

We asked William Sommers, Jr., head engineer and installer for Mist Air. He says, "On a perfect day, you can get up to 30 degrees."

We checked with Dr. Sonal Haerter from St. Joseph's Hospital to see if that was the case. She agreed with Sommers.

"Misters are very similar to sweat, and cool our body down," Haerter said. "So if you think about it, misters in dry weather can bring down the environmental temperature by about 30 degrees Fahrenheit."

But when the monsoon hits and the humidity is high, can misters still cool you down?

Dr. Haerter said they won't work as well with humidity, especially when it's more than 80 percent. Basically, you'll just get wet.

"They're not as effective as they are when it's a drier weather," she said.