Key numbers
45 verified hail storms with stones of 1.75 inches or larger reached Denver County from 1984 to 2026 in the storm records we keep; the largest measured 4.5 inches (softball size) on July 13, 2011 (NOAA NCEI).
| Hail storms by decade, 1984 to 2026 | 1980s: 1, 1990s: 4, 2000s: 12, 2010s: 17, 2020s: 11 Source: Storm library: Denver metro hail history |
|---|---|
| Largest hail | 4.5 in. (softball), July 13, 2011 Source: NOAA NCEI |
| Costliest hail storm | $2.3 billion insured losses (2017 dollars), May 8, 2017 Source: RMIIA |
| 51.3% | Denver County, Colorado has greater wildfire risk to homes than 51.3% of U.S. counties, per the USDA Forest Service's Wildfire Risk to Communities. Source: USDA Forest Service (Wildfire Risk to Communities) |
| 167 | NOAA's Storm Events Database logged 167 hail reports in Denver County, Colorado from 2010 through 2025, 140 of them 1 inch or larger. Source: NOAA National Centers for Environmental Information (NCEI), 2010-2025 |
| 52.0% | The USDA Forest Service rates wildfire likelihood in Denver County, Colorado as 'medium', higher than 52.0% of U.S. counties. Source: USDA Forest Service (Wildfire Risk to Communities) |
A storm counts when the library lists Denver County among the areas it hit. Each hail size is the storm's largest report, which may have fallen in a neighboring county, and insured losses cover every area the storm hit.
Vinyl siding costs less up front than most alternatives and needs no paint, but on Denver homes it has two real weaknesses: hail can crack or puncture it, and wildfire codes restrict it on mapped parcels in the foothill suburbs. It also moves a lot with temperature, so installation has to allow for that. This page compares vinyl honestly. Integrity Roofing and Painting mainly installs James Hardie fiber cement when we replace siding on existing homes, and we describe vinyl here so you can weigh the options.
The standard vinyl has to meet
Under section R703.11 of the International Residential Code, vinyl siding must be certified and labeled as conforming to ASTM D3679. Unless the manufacturer says otherwise, horizontal vinyl is fastened no more than 16 inches apart, and vertical siding no more than 12 inches. ASTM D3679 covers dimensions, impact strength, expansion and wind load. It is a floor, not a rating for hail.
How vinyl handles Front Range weather
Hail. In Haag Engineering’s ice-ball impact study, common vinyl profiles fractured at ice sizes between three-quarters of an inch and about an inch and a quarter, with foam-backed lap the weakest and a thicker Dutch lap the strongest. The bottom lap was the most vulnerable spot. Hail of that size is ordinary in Denver summers. Lab ice is denser than real hail, so treat the numbers as rough guides.
Sun and cold. Vinyl softens in heat and gets brittle in cold, and dark colors absorb more heat. A summer hailstorm and a January impact affect it differently, but both can break it.
Wind. Wind pulls at vinyl as well as pushing on it. The Vinyl Siding Institute’s 2020 wind research summary notes that the industry now publishes design pressure ratings and prints them on product box labels. Ask for that rating and compare it to your site’s wind design value.
Movement. Vinyl must hang loose on its nails with room at each end to slide. When it is nailed tight, it waves in the sun.
Wildfire rules
The Colorado Wildfire Resiliency Code, where a city or county has adopted it, limits exterior walls on moderate and high parcels to noncombustible, fire-retardant-treated wood or ignition-resistant coverings, and allows vinyl only as an exception over a wall built as a fire-resistance-rated assembly. Replacing 25 percent or more of the wall area triggers those rules. The Building America Solution Center’s comparison table rates vinyl low on both fire and wind/hail resistance. See WUI siding, eaves and decks for the full rule.
Vinyl compared with the alternatives
| Vinyl | Fiber cement | Engineered wood | |
|---|---|---|---|
| Code standard | ASTM D3679 (R703.11) | ASTM C1186 (R703.10) | Manufacturer evaluation report |
| Combustible | Yes | No | Yes |
| Paint | Not needed | Primed or factory finish | Factory finish or site paint |
| Hail | Cracks and holes | Chips and broken boards | Dents and splits |
| Allowed on mapped wildfire walls | Only over a rated wall | Yes | Only if tested and listed |
Read engineered wood siding, how to choose siding for Colorado and James Hardie fiber cement siding for the other options.
If your vinyl is already damaged
Cracked panels after a storm are covered in hail-damaged vinyl siding. If you are thinking about replacing it, our Denver siding replacement page explains how we tear off, flash and re-side, and the hail-damaged siding and insurance guide covers documentation and policy terms.
Get a siding recommendation
Integrity Roofing and Painting is veteran-owned and family-run since 1990, an Owens Corning Platinum Preferred roofing contractor with 650+ Google reviews. Call our Denver office at (303) 209-0152 or book a free inspection; we respond the same business day.
Sources: 2021 IRC section R703.11 (UpCodes); Haag Engineering, Ice Ball Impact Testing of Siding, 2012 (IIBEC); Vinyl Siding Institute, 2020 Wind Performance Research; Vinyl Siding Installation Manual; Building America Solution Center, Fire-Resistant Wall Assemblies; Colorado Wildfire Resiliency Code (DFPC).
