Coloradans love to brag about our 300 days of sunshine. The truth is closer to 245 fully sunny days plus another 50 or so with partial sun — which is still more than almost anywhere else in the country. That sun is one of the best reasons to build a deck here, and it's also the single biggest enemy of every deck we build. If you understand what the climate is doing to your outdoor space, you can build something that lasts. If you don't, you'll be re-staining or replacing boards a lot sooner than you should.
The Numbers That Matter
Sunny days per year: Denver averages 245 clear days and 115 days with measurable sun-plus-clouds. Colorado Springs and Pueblo run slightly higher.
UV intensity at altitude: UV radiation increases roughly 4% for every 1,000 feet of elevation. At Denver's 5,280 feet, UV is about 20–25% stronger than at sea level. In the high country, it's 40–60% stronger.
Temperature swing: It's not unusual to see a 50°F day-to-night swing in spring and fall. That's brutal on deck materials.
Snow load: Front Range averages 50–60 inches of snow per year, all of which sits on, melts into, and refreezes inside your deck.
Hail: Colorado is in the top three U.S. states for hail damage claims. A 1-inch stone falls at about 50 mph.
What This Climate Does to Decking
Wood fades and dries faster than the manufacturer's chart predicts. A redwood or cedar deck rated for "re-stain every 3 years" in Ohio realistically needs attention every 18–24 months in Colorado. UV breaks down lignin in the wood and pulls oil out of the surface. Without re-treatment, boards check, cup, and split.
Dark composite gets very hot. A standard dark composite board in direct Colorado sun can hit 160°F surface temperature on a 90°F day. That's hot enough to be uncomfortable barefoot and hot enough to soften lower-grade boards. Cool-surface capstock technology (TimberTech CoolDeck, Trex Transcend Lineage) cuts this by 30–35°F and is worth every penny on south- and west-facing decks.
Freeze-thaw cracks fasteners and substructure. Water gets into screw holes, freezes, expands, and works the fastener loose over many cycles. Hidden fasteners and stainless or coated structural screws aren't a luxury here — they're how you build a deck that's still tight in year 15.
Hail dents soft materials. PVC and lower-density composites can show hail dimples after a serious storm. Capped composites and aluminum hold up best. Wood actually does fine — it dents but you can sand it.
Snow and ice accelerate everything. Snow piled on a deck for weeks at a time keeps the surface saturated and can damage finishes. Plastic shovels only — metal edges gouge composite and PVC.
What to Build With Here
If you're building or replacing a deck along the Front Range, our material recommendations shift compared to lower-altitude, lower-sun regions:
- Composite or PVC with a UV-stable cap and a fade warranty of 25+ years. Almost every major brand qualifies, but check the warranty fine print — fade warranties in mountain markets often have specific exclusions you want to know about.
- Light-to-medium colors unless you specifically order cool-surface technology. Save the deep espresso boards for shaded decks or covered patios.
- Hardwood (Ipe, Cumaru) over softwood if you want real wood. Density makes them far more UV-tolerant. Plan on annual oiling or accept the silver-gray patina.
- Stainless steel or polymer-coated structural fasteners throughout. Standard galvanized is a false economy.
- A shade structure — pergola, polycarbonate cover, or shade sail — if the deck faces south or west. You'll use the deck more, and the deck will last longer.
Quick Climate Checklist Before You Build
Before signing a contract for a deck in Colorado, make sure your contractor has answered:
What direction does the deck face, and how many hours of direct sun per day? Is the chosen material's fade and heat warranty valid at our elevation? Are fasteners rated for freeze-thaw cycling? Is there a drainage plan for snowmelt? Is there a shade option in the design or budget?
The Bottom Line
Colorado's sun is a feature, not a bug — it's why we build decks in the first place. But the same UV that makes your backyard amazing in July is also burning the finish off your boards. Pick materials and finishes built for our climate, plan for shade, and budget for slightly more frequent maintenance on natural wood than the national averages suggest. Done right, a Colorado deck is the best room in the house.
