Olympia Climate Zone & Energy Code

Climate Zone: IECC Climate Zone 4C (marine Pacific Northwest). Olympia's South Sound position is one of western Washington's wettest locations — 86°F cooling design and 23°F heating design. Higher annual rainfall than Seattle; the mild marine climate produces substantial winter heating loads from long, overcast, wet seasons.

Energy Code & Manual J Requirement: Washington Energy Code (IECC 2021, Washington modified). ACCA Manual J required for residential HVAC permits in Thurston County and all Olympia area jurisdictions.

Local Electric Utility: Puget Sound Energy (PSE)

Building Department: City of Olympia Community Planning & Development

Local Trade Association: ACCA Northwest Chapter