BOISE, Idaho – Frost clings to rooftops and pastures across the Treasure Valley this morning, glittering in the first pale sunlight. Temperatures plunged into the upper 20s before dawn, sealing the region’s first hard freeze of the season and signaling the true start of late fall in southwest Idaho.
According to the National Weather Service in Boise, the Freeze Warning remains in effect until 10 a.m. Tuesday, covering much of the lower Snake Plain and extending west into eastern Oregon. Subfreezing readings between 28°F and 32°F have been observed around Nampa, Caldwell, and Ontario. Residents are urged to protect outdoor plumbing and move sensitive plants indoors, as frost damage may already be widespread in unprotected gardens.
The chill won’t last long. Clear skies and light winds will help Boise rebound into the low 60s this afternoon, with mid-60s Wednesday and near 70°F by Friday. Winds remain calm through midweek, providing excellent conditions for outdoor work, late harvest, and Halloween decorating.
A noticeable shift arrives late Friday as a Pacific front slides inland. Clouds increase across Ada and Canyon counties, bringing a 40–70% chance of showers from Friday night into Saturday. Some mountain locations could see early flakes above 6,000 feet, marking the season’s first hint of winter.
For now, the Treasure Valley enjoys two more mild, golden days before the weekend turns wetter and cooler — a final reminder that Idaho’s gentle fall warmth rarely lingers for long.
Five-Day Forecast for Boise, ID:
Tue: 62/39 – Sunny and calm; freeze early, milder later.
Wed: 64/40 – Mostly sunny; light breeze, pleasant air.
Thu: 64/43 – Sunny; calm, comfortable afternoon.
Fri: 71/48 – Partly sunny; breezy late, rain chance grows.
Sat: 51/43 – Showers likely; cooler with early fall chill.
