Hail history in Duncan, IA
Radar has detected major hail over the Duncan area on 31 days since 2011, up to 4" (baseball size or larger) on July 10, 2017. Source: NOAA Severe Weather Data Inventory radar signatures, which estimate hail aloft near Duncan, not confirmed ground reports.
Data last updated: July 26, 2026
Every major hail day near Duncan
What this record means for a Duncan roof
The list above covers 31 radar-confirmed hail days over Duncan between 2012 and 2026. The largest signature recorded over the Duncan area was 4" (baseball size or larger) on July 10, 2017. Radar put the local estimate at or above the 1" mark, the size generally capable of damaging asphalt shingles, on every one of those days.
Insurers and their adjusters can pull this same NOAA archive, so a date on this list is not news to the company handling a claim. What the archive cannot show is the condition of your specific roof, which is why dated photos and a written inspection report carry the weight in a dispute. Most homeowner policies also set a deadline to report storm damage, commonly one or two years from the date of loss, so a recent date above matters most if the roof was never inspected after it.
Get the roof inspected, free
Radar cannot confirm what hit your shingles; an inspection can, and it costs you nothing. Angi matches you with licensed local roofers who inspect for free and bid the work. Know how it works going in: the roofers pay Angi for the introduction, you pay nothing, and more than one company may call. That is the useful part: multiple written estimates are exactly what you want in hand before an adjuster visit or a contract.
Find licensed roofers near you on AngiReferral disclosure: this site may earn a fee if you request quotes through this link. That does not change what you pay, and no contractor pays to be described a certain way here.
Before you sign anything, read the contractor red flags: assignment-of-benefits traps, deductible games, and storm-chaser tells.
Common questions
Has Duncan had hail big enough to damage roofs?
Radar has detected hail up to 4" (baseball size or larger) over the Duncan area, most recently on June 28, 2026. Hail of 1" or larger is generally considered capable of damaging asphalt shingles.
Does this prove my roof was damaged?
No. Radar estimates hail aloft, accurate to roughly a mile, and cannot confirm what reached any specific roof. It is a strong reason to document your roof and check your policy's claim deadline after a listed date, not proof of damage.
How do I check my exact address in Duncan?
Use the free address lookup on this site. It searches the same NOAA radar archive within a radius you choose around your address, back to 2011.
If one of these dates is recent
- The first 48 hours : what to photograph and do before anything gets repaired.
- Contractor red flags : worth reading before signing anything a door-knocker hands you.
- The printable Playbook : the whole claim, start to finish.