Cover your plants because there’s a frost advisory in effect Wednesday morning

IDAHO FALLS — A frost advisory will be in effect Wednesday morning on the first day of summer.

The National Weather Service in Pocatello issued a frost advisory on Tuesday for Wednesday morning from 2 a.m. to 9 a.m.

“Temperatures as low as 32 could result in frost formation. Coldest temperatures are expected in the more rural areas with urban areas likely bottoming out in the upper 30s to around 40,” the advisory said.

There was originally a frost advisory issued Monday night after 8 p.m. and it expired Tuesday at 9 a.m., but it is back in place due to the cold temperatures.

NWS Pocatello posted on Facebook Tuesday morning before the expiration, “There is currently a frost advisory out for portions of the Snake Plain. We’ve never had a frost advisory in effect in southeast Idaho this close to the start of summer (at least since 2005). Expect even colder temperatures tomorrow — the first day of summer!”

“For frost, the rule of thumb is 32 to 36 degrees so it’s a fairly narrow window and anything colder than that, you get a freeze warning, especially if the 32-degree temperatures last more than one hour,” explained Jack Messick, a meteorologist with NWS in Pocatello.

The areas affected for Wednesday morning under the frost advisory include Shoshone, Richfield, Carey, Mud Lake, INL, Craters of the Moon, Idaho Falls, Rexburg, St. Anthony, Pocatello, Blackfoot, American Falls, Shelley, Fort Hall, Burley, Rupert, Heyburn and Oakley.

Messick explained what eastern Idaho could expect for morning temperatures.

“Some of the colder places are Arco 32 (degrees), Mud Lake 34 degrees, St. Anthony 33, Dubois 34 and then Rexburg, Rigby and Idaho Falls all 35 degrees, and 36 in Blackfoot,” Messick said.

The frost could kill sensitive outdoor vegetation if left uncovered, the frost advisory said.

“If you have a concern out there, obviously with those that aren’t necessarily farmers, but are more backyard vegetable growers, they might have to consider how to protect their plants,” Messick said. “Bring plants in if they are potted.”

He said it will most likely warm up next week.

“Until this Sunday, when things actually start to clear up…we will be above or right at normal, maybe the first part of next week. We will be back into the 80s and maybe 70s,” Messick said.