How Close is Boise to Experiencing Its First Sizzling 100 Degree Day?

“Cute how a week from Friday thinks it can sneak in and no one’s going to notice.” Our friend Kevin posted that on Facebook, along with a screenshot that none of us were expecting to see. 

Boise’s June weather has been quite the roller coaster. We experienced several days of severe thunderstorms that caused jaw-dropping flash flooding and dozens of downed trees. The one on June 6 actually created the most lightning strikes Ada County has experienced since 2000. 1,449 were recorded that evening. 

Flash forward to this week? It started with unseasonably cool weather. In fact, Boise set a record for the lowest high temperature recorded for June 19. The mercury didn’t rise about 62 degrees on Monday, something that feels weird to say just two days before the official arrival of Summer in the Treasure Valley. 

Wednesday, June 21 marked the first day of astronomical summer, so naturally, a lot of us are wondering “so when is it finally going to feel like summer?” The screenshot we mentioned earlier seemed to give us a hint. Kevin shared a screenshot of the weather app on his iPhone where the high jumps from 88 on Thursday, June 29 to 104 on Friday, June 30! 

Get our free mobile app

If you’re thinking “I’m not ready for triple digits yet,” exhale. A few hours after he posted that photo, the forecast had already shifted. The iPhone weather app is now showing a high of 91 on June 30. KTVB is showing 92. So is Weather Underground. In fact, there are no extended forecasts showing that Boise will hit 100 anytime between now and July 5. 

Is that unusual? Not really. We dug through historical data from the last 15 years to find out when the area typically experiences its first triple digit day. Boise’s first triple digit day typically happens around July 1. In the last 15 years the earliest it happened was June 3, 2021 when it hit 103. The latest it happened was July 22, 2019 when it finally hit 102. 

Why the fascination with triple digit days? Many of us are waiting to see if we come close to the record setting year we experienced in 2022. Last year, we set a record for the most triple digit days in an entire year at 27. 2022 only had one triple digit day in June (June 27.) 14 of those fell in July, eight were in August and four were in September.