What Climate Zone is Yolo, California?

Yolo is in IECC Climate Zone 3B (Warm - Dry). Get accurate Manual J load calculations with official design temperatures for Yolo.

Climate Zone
3B
Winter Design
35°F
Summer Design
99°F
ZIP Codes
21

Yolo, California falls within IECC Climate Zone 3B (Warm - Dry), a mixed-climate region with dry moisture conditions. HVAC contractors working in Yolo must use the official ASHRAE design temperatures of 35°F (99% winter) and 99°F (1% summer) when performing Manual J load calculations. These values represent the outdoor conditions your heating and cooling system must handle 99% and 1% of the year, respectively — ensuring proper equipment sizing without costly over- or under-sizing.

Zone 3B experiences both significant heating and cooling loads. Yolo homes need balanced insulation — R-20 walls, R-30 ceilings — plus windows with U-factor 0.32 and SHGC 0.25 per the IECC 2021 energy code.

Yolo Insulation Requirements (IECC 2021)

Minimum insulation R-values and window performance requirements for Climate Zone 3B in Yolo, California.

Building ComponentMinimum RequirementUnit
Ceiling / Attic InsulationR-30R-value
Wall InsulationR-20R-value
Floor InsulationR-19R-value
Window U-Factor0.32BTU/hr-ft²-°F
Window SHGC0.25Coefficient
Air Infiltration0.15ACH50

Yolo HVAC Contractors: Get Your Free Manual J Report

Climate Zone 3B requires precise load calculations. Upload your Yolo blueprint and get a professional Manual J report in 60 seconds— first report is FREE. Pre-loaded with Yolo's exact design temperatures (35°F winter / 99°F summer).

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Verify Your Yolo ZIP Code

Enter your ZIP code to confirm it's in Yolo and get climate zone details.

Yolo covers 21 ZIP codes: 95605, 95606, 95607, 95612, 95616, 95618, 95627, 95637, 95645, 95653 and 11 more

Yolo Design Temperatures

Official ASHRAE design temperatures for Yolo, used for accurate Manual J load calculations.

Winter 99% Design Temp
35°F
Summer 1% Design Temp
99°F
Summer Wet Bulb
68°F

IECC Requirements for Zone 3B

Minimum insulation and window requirements for Yolo per IECC 2021.

Wall Insulation:R-20
Roof/Ceiling:R-30
Floor Insulation:R-19
Window U-Factor:0.32
Window SHGC:0.25

Energy Code: 2022 Title 24

Recommended HVAC Equipment for Yolo

Heating Systems

Gas furnace
Heat pump
Typical AFUE
90-95%

Cooling Systems

AC (14-16 SEER)
Typical SEER
14-16 SEER

Get Free Manual J Calculations for Yolo

Upload your Yolo blueprint and get a professional Manual J load calculation using official Zone 3B design temperatures. First report is FREE.

Yolo design temps
Zone 3B compliant
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