Climate Zone 10: Inland Empire & Inland San Diego
Hot summers with significant cooling demand and cool winter nights.
Every Title 24 energy calculation uses the climate zone of the building’s physical location. In Zone 10, the climate is cooling-dominated, which shapes which building features have the most effect on compliance.
Typical project considerations
- High cooling loads — high-performance windows and insulation pay off.
- PV production is strong.
General guidance only — requirements depend on building type, scope and the code edition in effect for your permit application.
Example communities
Riverside · San Bernardino · Escondido
City guides: San Diego · Riverside
Official references
Frequently asked questions
Where is California Climate Zone 10?
Climate Zone 10 (Inland Empire & Inland San Diego) covers areas such as Riverside, San Bernardino valleys, inland San Diego. Its representative weather city in CEC data is Riverside. Boundaries don’t follow city limits, so confirm by address.
Does Climate Zone 10 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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