Boise just broke a 33-year-old heat record. Here’s when temperatures will drop
How hot is Boise? The City of Trees just broke a 33-year-old temperature record, according to the National Weather Service.
Boise hit a high temperature of 96 degrees at 5:47 p.m. on Tuesday, May 12, the weather service said.
The previous maximum record for May 12 — 94 degrees — was set in 1993.
“It was also the earliest date for 96 degrees since records began in 1875,” the National Weather Service wrote in a Tuesday post on X. “Until today Boise had never been that hot before May 24.”
It’s not the first time this spring that Boise has broken a heat record.
In mid-March, Boise recorded its earliest 80-degree day to date.
More recently, unseasonably warm weather has pushed temperatures in Boise almost 30 degrees above average, according to the weather service.
How long will warm temperatures last?
Much of Idaho was expected to see a “significant pattern change” on Wednesday as a Pacific low-pressure system brings in a “strong cold front,” the National Weather Service said in its most recent state forecast discussion.
“Northern portions of the state can expect showers and thunderstorms along and near the front, with gusty winds a strong possibility,” the weather service said in the forecast. “Southern areas can expect strong winds along and behind the front, but little chance of precipitation.”
That means a dramatic drop in temperatures.
What’s in the weather forecast for Boise?
On Wednesday, Boise was expected to see a high temperature around 80, according to the National Weather Service’s latest seven-day forecast.
Seasonal temperatures for mid-May are typically in the low 70s, according to the weather service.
Wednesday’s forecast also called for winds of 18 to 23 mph, with gusts as high as 40 mph.
The weather service issued a wind advisory for parts of south-central and southwest Idaho, including the cities of Boise, Caldwell, Nampa and Twin Falls, that will remain in effect until midnight Wednesday.
Gusts could reach 55 mph, the weather service said.
Cooler temperatures will return Thursday, which will have a high of 74 and a low around 46.
On Friday, the temperature could reach a high of 71 before cooling to a low of 45.
Heading into the weekend, Boise will see highs in the high 50s or low 60s, with lows in the high 30s.
How to stay safe in the heat
When temperatures are extremely high, some people’s bodies can have trouble regulating temperature.
In some cases, people can experience heat exhaustion and have muscle cramps, nausea, weakness and cold or clammy skin, according to the Centers for Disease Control and Prevention.
If heat exhaustion persists for too long, however, it can lead to heatstroke, the most serious form of heat injury.
People experiencing heatstroke can have hot, red, dry or damp skin. They also can have a fast and strong pulse, and they can become confused. You should move indoors immediately and call 911 right away if you have these symptoms.
If you choose to hike or be outdoors in dangerously hot temperatures, officials recommend the following tips:
- Carry and drink plenty of water and plan to replenish electrolytes.
- Eat twice as much food as normal and have salty foods on hand.
- Carry a first-aid kit.
- Pack essentials only.
- Bring a flashlight with spare batteries to hike during the cool evening.
- Spray yourself with water to cool down.
- Have a hat and sunscreen as protection from the sun.
- Have a whistle or signal for emergency use.
- Wear waterproof clothing if needed.
This story was originally published May 13, 2026 at 3:11 PM.
