Corona, CA: Climate Zone, Risk and Window Requirements

Corona sits in IECC climate zone 3B, which sets the energy-performance bar for any window installed here. Below that, a short list of Corona's longest-licensed window contractors can turn a spec into an actual installed window.

Licenses checked September 30, 2026 · California Contractors State License Board

3BIECC climate zone · ENERGY STAR South-Central zone

Corona's climate zone, in plain terms

Riverside-San Bernardino-Ontario, CA runs a January average near 56°F and climbs to about 78°F by July, a swing that adds up to roughly 1,387 heating degree days most winters, with 1,817 on the summer cooling side of the ledger.

That load is the actual argument for paying up for a better U-factor in Corona, separate from anything a brochure claims.

Zone 3B's requirement is the floor; Corona's specific load is what tells you whether beating that floor is worth the extra cost.

Data: U.S. EPA / DOE, ENERGY STAR, ENERGY STAR Version 7.0 Climate Zones by County/ZIP (Windows, Doors, and Skylights) (V7.0); Pacific Northwest National Laboratory (DOE Building America), Guide to Determining Climate Zone by County: Building America and IECC 2021 Updates (PNNL-33270) (2021 IECC), from the nearest NOAA station 8.8 mi away.

What FEMA's risk data says about Corona

FEMA scores Riverside County's winter-weather risk as Relatively Moderate and its flood risk as Very High.

Winter risk in Corona weighs on U-factor and condensation resistance; flood risk weighs more on sill height and drainage detailing than on the glass package.

Treat these as two separate conversations with a Corona contractor, not one.

Hurricane: Very Low
Strong wind: Relatively Moderate
Winter weather: Relatively Moderate

Data: FEMA, National Risk Index for Natural Hazards - County-level table, v1.20 (v1.20, December 2025).

Guides to finish before Corona window bids come in

How to Read an NFRC Window Label Four numbers on one sticker decide most of a window's real-world performance. Here's what each one means.
ENERGY STAR Window Criteria by Climate Zone ENERGY STAR splits the country into four zones, each with its own numbers. Here they are, and why the Northern zone works backward from the other three.
Impact Windows vs. Shutters in Florida's Hurricane Zones Florida gives homeowners two paths to a protected opening. Here's how each one is tested, and where the HVHZ raises the bar further.

Corona's longest-licensed window installers

Oldest license first, newest last, pulled directly from the state's file. This list isn't for sale.

Randy Jones ConstructionWindow and glass contractor · licensed 41 years · 92881Verify license
Green's Shower Door & Mirror INCWindow and glass contractor · licensed 37 years · 92878Verify license
Gpa Doors & Windows INCWindow and glass contractor · licensed 37 years · 92878Verify license
Steel City Glass IncorporatedWindow and glass contractor · licensed 36 years · 92882Verify license
All Pro Glass And ScreenWindow and glass contractor · licensed 26 years · 92878Verify license
Glazing Concepts INCWindow and glass contractor · licensed 25 years · 92878Verify license
Alex The Glass ManWindow and glass contractor · licensed 22 years · 92882Verify license
Temescal Valley GlassWindow and glass contractor · licensed 22 years · 92883Verify license
T W GWindow and glass contractor · licensed 19 years · 92881Verify license
D B E INCWindow and glass contractor · licensed 16 years · 92883Verify license
S R Windows And Doors SpecialistWindow and glass contractor · licensed 15 years · 92882Verify license
Exterior Glazing SystemsWindow and glass contractor · licensed 15 years · 92881Verify license

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