Rancho Cucamonga Climate Zone & Energy Code
Climate Zone: CEC Climate Zone 10 (western Inland Empire / San Bernardino foothills). IECC Climate Zone 3B. Rancho Cucamonga's foothill position tempers the heat slightly compared to the valley floor — 100°F cooling design and 31°F heating design. Mountain air drainage provides overnight cooling relief not available in the flat Inland Empire to the east.
Energy Code & Manual J Requirement: California Title 24 Part 6 (2025 edition, effective January 1, 2026). ACCA Manual J required for residential HVAC sizing. All Rancho Cucamonga and San Bernardino County jurisdictions enforce Title 24.
Local Electric Utility: Southern California Edison (SCE)
Building Department: City of Rancho Cucamonga Building & Safety Services
Local Trade Association: ACCA California