BOISE, Idaho – A chilly fall start greets the Treasure Valley as Idaho’s Frost Advisory remains in effect through 9 a.m. Saturday, signaling the first widespread frost of the season. Temperatures dipping into the mid-30s could threaten gardens and outdoor plants across Boise, Nampa, and Caldwell before the weekend warms back up.
According to the National Weather Service in Boise, clear skies and calm winds overnight allowed cold air to settle into the lower Snake Plain. Residents are urged to cover sensitive vegetation and bring in potted plants to avoid frost damage. The advisory includes the entire Treasure Valley and western Magic Valley, where morning lows between 33°F and 37°F will briefly form frost on exposed surfaces.
Saturday will bring sunshine and comfortable fall warmth, with highs climbing to near 64°F under light winds. Clouds build late in the day ahead of a weak Pacific system set to arrive Sunday. That system will bring a 60% chance of showers, mainly during the afternoon, along with cooler air and gusty breezes. Rain totals will stay light, but the change will be noticeable after the calm start to the weekend.
By Monday, skies clear again as sunshine returns and highs reach the upper 50s — classic mid-October weather for pumpkin patches, leaf peeping, and football fans. The rest of the week looks mild and quiet, offering a steady mix of cool mornings and bright, pleasant afternoons.
Bundle up early — but get ready to enjoy a beautiful, golden Idaho weekend once the frost melts away.
Five-Day Forecast for Boise, ID:
Sat: 64/47 – Sunny; frost early, pleasant afternoon.
Sun: 63/37 – Showers likely; breezy and cooler.
Mon: 58/37 – Sunny and calm; crisp fall air.
Tue: 62/40 – Mostly sunny; mild and dry.
Wed: 65/42 – Partly cloudy; light breeze.
