Missoula Climate Zone & Energy Code

Climate Zone: IECC Climate Zone 6B (cold-dry). Missoula's mountain valley location produces cold winters (-12°F heating design) with valley inversion events that can trap extremely cold air, very dry summers (58°F wet-bulb), and altitude derating (~89% of sea level at 3,200 ft).

Energy Code & Manual J Requirement: Montana Residential Building Code (IECC 2021). ACCA Manual J required for Missoula County HVAC permits.

Local Electric Utility: NorthWestern Energy

Building Department: City of Missoula Office of Planning & Grants

Local Trade Association: PHCC Montana / ASHRAE Montana Chapter