Climate Zone 2: North Bay & Inland North Coast
Coastal-influenced valleys with cool winters and warm, dry summers.
Every Title 24 energy calculation uses the climate zone of the building’s physical location. In Zone 2, the climate is mixed, which shapes which building features have the most effect on compliance.
Typical project considerations
- Both heating and cooling loads matter.
- Fenestration orientation affects summer comfort in valley sites.
- Wildfire-area construction requirements may interact with envelope choices.
General guidance only — requirements depend on building type, scope and the code edition in effect for your permit application.
Example communities
Santa Rosa · Napa · Ukiah
City guides: Santa Rosa
Official references
Frequently asked questions
Where is California Climate Zone 2?
Climate Zone 2 (North Bay & Inland North Coast) covers areas such as Sonoma, Napa, inland Mendocino. Its representative weather city in CEC data is Santa Rosa. Boundaries don’t follow city limits, so confirm by address.
Does Climate Zone 2 change my Title 24 requirements?
Yes. All Energy Code calculations use the project’s climate zone, which affects prescriptive values such as insulation and window performance and how heating and cooling are weighted in performance modeling.
What report do I need?
Single-family projects use CF1R, low-rise multifamily uses LMCC and nonresidential projects use NRCC forms — regardless of climate zone.
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