Methodology

How the report is built

Updated October 15, 2026

Every number in the report comes from a public US government record, and the report names the record it came from. Values are shown as published, never blended or smoothed. Here is what we use and how.

1. The location

The address is matched with the US Census Bureau Geocoder. When it can't be matched, for example a rural or new property, you place a pin on the map and the report says the location was set by pin. All distances are measured from that one point.

2. Measured weather at nearby stations

Wind, gusts, rain and temperature come from NOAA's Global Historical Climatology Network – hourly (GHCNh), the archive of hourly reports from airport and other weather stations. The report lists the nearest stations, each with its distance and direction from the property, and shows every report the station sent that day. It leads with the nearest airport station, because those measure wind to a common standard, unless another wind-measuring station is much closer.

A station measures the weather where it stands, not at the property. The distance is printed next to every reading so you can judge how close it is.

3. Warnings and the warning-area check

Every National Weather Service watch and warning for the day is taken from the Iowa Environmental Mesonet warning search archive of NWS products (Iowa State University), with the full bulletin text. For warnings drawn as an area on the map, the report checks whether the property's point was inside that area, and if not, how far outside it was.

4. Storm reports

NWS Local Storm Reports are what spotters, emergency managers, the public and automated stations reported on the day: hail sizes, measured and estimated gusts, damage, tornadoes. They are preliminary, and the report shows them as issued, sorted by distance from the property.

5. NOAA Storm Events

The NCEI Storm Events Database is NOAA's reviewed record of significant weather, including tornado paths. It is published a few months after each month ends. For recent dates the report says it is not published yet, which is different from "no event".

6. Radar hail and lightning

Radar hail detections come from NEXRAD radar via NOAA's Severe Weather Data Inventory. They estimate hail aloft from the radar, not hail measured on the ground. Lightning comes from the same inventory as daily strike counts per grid cell of about 6–7 miles. Individual strike locations are not public, so the report gives counts near the property, not exact strikes.

Distances and directions

Distances are straight-line miles from the property. Directions point from the property to the record, so "4.7 mi WSW" means the record lies west-southwest of the property. Some records have approximate positions: storm reports are often placed at the nearest town or road.

Same inputs, same report

Every source response is stored exactly as received, with a fingerprint (SHA-256 hash) and the time it was retrieved. The report ID is derived from those fingerprints, so the same ID always means the same PDF, and anyone can check the numbers against the original sources listed on the report's last pages.

What the report does not do

• It does not say whether weather caused damage, or whether a loss is covered.
• It is not a certified government record or an expert opinion. When you need one of those.
• Missing values are shown as missing, never as zero.
• It covers US addresses and dates from 2005 to yesterday. No forecasts.