Hail & hurricane history API

One endpoint answers what NOAA recorded near a U.S. address: radar-estimated hail since October 2019 and tropical storm and hurricane tracks since 1851. The same data as the $19 address report, as JSON. The widget uses it too.

Keys

Sign in at your account and open API & widget. There are two kinds of key:

• Secret key hm_sk_… — for your server. Send it in the Authorization: Bearer or X-API-Key header. It is shown once; we keep only its SHA-256 hash. Requests from a browser (with an Origin header) are refused, so it cannot leak through a web page.
• Public key hm_pk_… — for the widget and your own browser code. It works only from the domains listed in your account (https, with and without www; localhost for testing), with CORS.

Never put a key in the URL: a request with ?key= is refused. Revoke a key in the account at any time.

GET /v1/history

Parameters: address (one line, up to 200 characters, geocoded by the U.S. Census Geocoder) or lat and lon (contiguous United States).

curl -H "Authorization: Bearer hm_sk_…" \
  "https://myhailmap.com/v1/history?address=222%20W%20Main%20St%2C%20Pensacola%2C%20FL%2032502"

curl -H "X-API-Key: hm_sk_…" "https://myhailmap.com/v1/history?lat=40.8093&lon=-96.7011"

// browser, public key, from a listed domain
const r = await fetch('https://myhailmap.com/v1/history?address=' + encodeURIComponent(address), {
  headers: { 'X-API-Key': 'hm_pk_…' }, credentials: 'omit',
});
const body = await r.json();
if (!r.ok) throw new Error(body.error.message);
console.log(body.hail.days.length, body.hurricanes.systems.length);

Response

{
  "point": { "lat": 30.406892, "lon": -87.217973, "matched_address": "222 MAIN ST, PENSACOLA, FL, 32502" },
  "data_through": "2026-10-27",
  "hail": {
    "since": "2019-10-01", "radius_km": 5,
    "days": [ { "date": "2026-03-07", "max_in_1km": null, "max_in_3km": null, "max_in_5km": 0.82, "nearest_report": null }, … ],
    "date_of_loss": { "last_1in_within_1km": null,
                      "last_1in_within_3km": { "day": "2025-10-26", "size_in": 1.02, "days_ago": 366 },
                      "largest_within_1km": { "day": "2023-04-27", "size_in": 0.91, "days_ago": 1279 } },
    "ground_reports": [ { "date": "2026-03-15", "time_utc": "2026-03-16T11:35:00Z", "size_in": 1, "distance_km": 7.3,
                          "place": "BRENT, FLORIDA", "source": "NCEI Storm Events" }, … ],
    "source": "…", "note": "…"
  },
  "hurricanes": {
    "radius_mi": 75, "first_season": 1851, "last_season": 2025,
    "systems": [ { "id": "AL192020", "name": "Sally", "year": 2020, "basin": "AL", "closest_mi": 22.9, "wind_at_closest_kt": 82,
                   "max_wind_near_kt": 95, "category_near": 2, "peak_wind_kt": 95, "closest_date": "2020-09-16" }, … ],
    "strongest": { "id": "AL111979", "name": "Frederic", "year": 1979, "category_near": 4, "closest_mi": 61.1, … },
    "compare": { "recent_from": 1996, "recent_to": 2025, "recent_count": 13, "recent_per_decade": 4.3,
                 "before_from": 1851, "before_to": 1995, "before_count": 58, "before_per_decade": 4 },
    "source": { "name": "NOAA National Hurricane Center HURDAT2", "url": "https://www.nhc.noaa.gov/data/#hurdat" },
    "note": "…"
  },
  "attribution": { "required": true, "text": "Powered by Hail Maps", "url": "https://myhailmap.com/widget" },
  "disclaimer": "Historical NOAA data. Not a forecast, not an official National Weather Service …",
  "usage": { "charged": true, "month_used": 12, "month_limit": 50, "day_limit": 5, "plan": "Free" }
}

• hail.days — every day with radar hail (MESH) within 5 km, newest first; maximum estimated size in inches within 1, 3 and 5 km (null when none in that ring) and the nearest ground report that day within 10 km.
• hail.date_of_loss — the latest day with 1" or larger within 1 and 3 km, and the largest within 1 km.
• hail.ground_reports — up to 15 NOAA SPC and NCEI Storm Events reports within 10 km, newest first.
• hurricanes.systems — every system that came within 75 miles as a tropical storm or hurricane (HURDAT2 status TS or HU), newest first: closest distance from the point to the track centre line, wind there, the highest wind and Saffir-Simpson category while within 75 miles (0 = tropical storm), the peak of the whole track and the date of the closest approach.
• hurricanes.compare — the last 30 seasons against all earlier ones, per decade; records before satellites (mid-1960s) miss some storms.
• attribution — when required is true (Free), show the “Powered by Hail Maps” link next to the data.

Limits

A look-up is one new address or point: asking again about the same place within 30 days is free. Limits reset on the 1st of the month and at midnight (UTC). Paid plans renew monthly through Dodo Payments and can be cancelled at any time in your account.

Each response carries X-RateLimit-Limit (look-ups a month), X-RateLimit-Remaining, X-RateLimit-Reset (Unix time of the next month) and X-Lookup-Charged. Bursts: up to 30 requests in 10 seconds per key. Address searches that find nothing and requests that fail are not counted.

Errors

Errors are JSON: {"error": {"code": "monthly_limit", "message": "…"}}.

Data and terms

Hail: NOAA MRMS MESH radar estimates (0.01° grid, daily maxima) and NOAA/NWS ground reports. Hurricanes: NOAA National Hurricane Center HURDAT2 (Atlantic since 1851, north-east and central Pacific since 1949). Historical data, not a forecast and not an official National Weather Service warning; not an inspection, insurance or legal advice. Use is subject to the API terms. Questions: support@myhailmap.com.