Temperatures in Boise over the weekend were running about 15 degrees above normal, peaking at a record high of 104 on Sunday, according to the National Weather Service. The previous record for June 30 was 103 in 1950.
And it's going to get hotter.
Weather Service forecasters expect Boise to break another record on Monday, possibly reaching 108. The record high for July 1 was 104 in 1924.
Air quality is expected to diminish Monday. The Idaho Department of Environmental Quality issued a "yellow" air alert.
The forecast Air Quality Index is 67, and that means all open outdoor burning is prohibited throughout Ada County, including all of the incorporated cities. It is also prohibited in the incorporated cities within Canyon Count. Individuals in sensitive groups, including the elderly and children, should limit activities outside. Everyone is asked to limit driving, combing trips and errands.
June was a warm month, with 10 days above 90. The ridge of high pressure now dominating the weather in the Western United States is shutting out cool air from the Pacific Ocean and Canada, said Weather Service lead forecaster Les Colin.
When was the last time it was 108 in Boise? Just last year. Twice. July 9 and July 12. July is Boise's hottest month of the year.
Some relief is on the horizon, if you consider high-90s relief. Tuesday and Wednesday will be in the triple-digits, but temperatures are expected to drop into the 90s on Thursday.
There's a chance of thunderstorms on Monday, but the best chance is on Tuesday, Colin said.