More thunderstorms are heading to Boise area amid ‘monsoonal moisture.’ See when
Thunderstorms and rain are on the way to the Boise area amid a major heat wave, according to the National Weather Service.
“Southwesterly flow from this ridge will steer monsoonal moisture into the region starting Monday,” the weather service said in the most recent Idaho state forecast discussion.
“This pattern will bring chances of showers and thunderstorms each afternoon (and) evening” through the week, “especially over the mountains,” the weather service said.
Here’s when the rain will fall:
When will showers start in Boise area?
“Isolated showers” were expected on Monday, July 13, the National Weather Service said in a post on X.
“Showers and thunderstorms will increase area-wide” on Tuesday and “will be capable of localized heavy downpours and outflow winds up to 40 mph,” the weather service said.
According to the National Weather Service’s most recent seven-day forecast for Boise, there is a 20% chance for precipitation on Tuesday afternoon.
However, forecasters advise Treasure Valley residents to be cautious of storm hazards on Monday as well.
How much rain will Boise get?
Showers were expected to begin overnight on Monday, resulting in half an inch to an inch of rain on Tuesday, according to Korri Anderson, meteorologist at the National Weather Service’s Boise office.
It’ll be “very muggy for Boise standards,” Anderson said.
Tuesday will see a high temperature of 91 with a dewpoint around 60, which is “very unusual for Boise,” Anderson said.
Precipitable water, which is the inches of moisture that air can hold directly above a single point, is approaching an all-time record of 1.5 inches set in 2008.
Anderson anticipated precipitable water to measure 1.2 inches on Tuesday.
What’s in the weather forecast for Boise?
According to the National Weather Service’s current seven-day forecast for Boise, Tuesday will have a high temperature of 91 and an overnight low of 64 as storms blow through town.
Temperatures increase Wednesday with a high near 97 and a low of around 64.
Highs for the remainder of the week will stay near 101 with overnight lows in the upper 60s.
Where are flooding risks in the Treasure Valley?
When storms develop, Boise-area residents may see hard, heavy downpours of up to an inch of precipitation all at once., according to Anderson.
Most storm cores are expected to rain over Eastern Oregon and south of the Snake River, the forecaster said.
Due to flooding risks heightened by the Claremont Fire’s burn scar, the National Weather Service is closely monitoring conditions of the Freestone Creek Basin near the Military Reserve.
Soil becomes hydrophobic after wildfires, which may increase chances of intense flooding and debris runoff in Boise.
Be prepared for floods before they happen
Floods are the most common natural disaster in the United States, according to the Department of Homeland Security. They can develop both slowly and quickly, and flash floods can come without warning.
If you’re under a flood warning or are experiencing flooding, officials say you should follow these steps to help keep you safe:
- Find safe shelter immediately.
- Don’t walk, swim or drive through floodwaters.
- Stay off bridges over fast-moving water.
- Stay in your car if it’s trapped in rapidly moving water, or go on the roof if the water is rising inside the vehicle.
- Evacuate if told to do so. Listen to local responders.
- Move to higher ground or if you’re trapped in a building, move to the highest possible level.
- Only get on your roof if necessary, and don’t climb into a closed attic.
This story was originally published July 13, 2026 at 5:10 PM.
