Hurricane category by wind speed

Winds below the tropical-storm threshold fail with invalid_input unless you opt into sub-categories for tropical depressions. The path is pure table logic—no forecast model, no network call, no clock—so education tools, insurance demos, and prepaid API clients pin identical JSON in tests.

Saffir-Simpson bands, inputs, and the tropical-storm threshold

The Saffir-Simpson Hurricane Wind Scale classifies Atlantic and eastern North Pacific tropical cyclones by peak one-minute sustained surface winds. After conversion to statute miles per hour, tropical storm spans thirty-nine through seventy-three miles per hour, Category one covers seventy-four through ninety-five, Category two ninety-six through one hundred ten, Category three one hundred eleven through one hundred twenty-nine, Category four one hundred thirty through one hundred fifty-six, and Category five begins at one hundred fifty-seven miles per hour and has no upper bound in this product. Optional unit defaults to mph and also accepts kn, kt, knots, km/h, and m/s with common spellings. Practical upper bound after conversion is four hundred miles per hour so classroom typos fail loudly. Tropical depression is the band strictly below thirty-nine miles per hour; that label is returned only when include_subcategories is true. If include_subcategories is false or omitted and the converted speed is still below thirty-nine miles per hour, the request fails with invalid_input and a message that names the tropical storm threshold, so callers do not silently treat a depression as a storm. Required field wind_speed is a non-negative finite number; aliases speed, wind, sustained_wind, and v are accepted. Optional include_subcategories accepts boolean true or false and common string forms. Identical inputs always yield identical JSON because the algorithm never touches the network, a model, a clock, or a random generator. Missing fields, negative winds, unknown units, and non-finite values all fail with invalid_input and are not charged.

Reading the response fields and how units convert

Conversion uses fixed international definitions: one statute mile is one thousand six hundred nine point three four four metres, one international knot is one nautical mile of one thousand eight hundred fifty-two metres per hour, and metres per second scale by three thousand six hundred over the statute-mile factor. On success the response echoes wind_speed and unit, then reports wind_speed_mph, wind_speed_kn, wind_speed_kmh, and wind_speed_ms so dashboards can show several columns without reimplementing conversion factors. Category is a stable machine key among tropical_depression, tropical_storm, category_1 through category_5, while category_label is the matching human phrase for UI chips and reports. Category_number is zero for depression and tropical storm and one through five for hurricanes; is_hurricane is true only for categories one through five so filters can separate named hurricanes from pre-hurricane tropical cyclones. Wind_range_mph and wind_range_kn restate the published band for the selected category, and damage carries a short typical-damage narrative aligned with National Hurricane Center style summaries for that band—not a site-specific forecast. Scale is always Saffir-Simpson Hurricane Wind Scale and method is always saffir_simpson_wind_category so downstream code can branch without sniffing shapes. Do not confuse this endpoint with Beaufort force converters, crosswind component tools, or numerical weather prediction—those answer different search intents and different physics.

API usage, pricing, product workflows, and practical limits

Call the free in-browser hurricane category lookup for classroom demos, coastal preparedness pages, and quick personal checks without reimplementing threshold tables in every spreadsheet. Prefer consistent units; if your UI collects knots from marine products, send unit kn rather than converting by hand. Keep expectations educational: this is a wind-band classification tool, not a storm-surge height model, track forecast, or evacuation order, and people under watches or warnings should follow official National Weather Service and emergency-management guidance rather than any single automated label alone. Send a JSON body with required wind_speed and optional unit and include_subcategories. Use the prepaid API when a newsroom CMS, insurance quote prototype, travel-risk SaaS, emergency-management worksheet, or school LMS needs a stable contract under KIT balance at $0.002 per successful item; validation failures never consume balance after the engine rejects the request. Pair this endpoint with your own source of sustained wind—advisory text, ASOS observations, or scenario inputs—then store category alongside the raw magnitude for dashboards and export CSV columns for wind_speed_mph, category, and damage. Authors shipping SDKs can map category and is_hurricane into colour bands and alert thresholds—the same ordered labels students and broadcasters learn from Saffir-Simpson teaching materials.