Climate Zone 15: Low Desert
Extremely hot summers with the highest cooling demand in the state.
Every Title 24 energy calculation uses the climate zone of the building’s physical location. In Zone 15, the climate is cooling-dominated, which shapes which building features have the most effect on compliance.
Typical project considerations
- Cooling efficiency and solar heat gain control are critical.
- Roof assemblies and window SHGC drive compliance.
General guidance only — requirements depend on building type, scope and the code edition in effect for your permit application.
Example communities
Palm Springs · Indio · El Centro
Official references
Frequently asked questions
Where is California Climate Zone 15?
Climate Zone 15 (Low Desert) covers areas such as Coachella & Imperial valleys. Its representative weather city in CEC data is Palm Springs. Boundaries don’t follow city limits, so confirm by address.
Does Climate Zone 15 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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