The unit commonly used for wind speed in official tropical cyclone advisories is the knot.
One knot equals exactly one nautical mile per hour, or 1.852 kilometers per hour. Meteorologists and mariners use knots because tropical cyclones are ocean-based systems, and the unit fits long-standing maritime and aviation practice. Advisory bulletins typically report sustained winds, wind thresholds, and forecasts in knots.
The knot is a unit of speed, not a distance or an acceleration. Saying “knots per hour” is therefore incorrect when describing speed; it would technically describe a rate of acceleration. The standard symbol is “kn,” although “kt” is also widely used, particularly in aviation.
Tropical cyclone categories and warning thresholds often use knot values. In the Atlantic and eastern North Pacific, for example, hurricane strength begins at sustained winds of 64 knots, equivalent to 74 miles per hour. Different agencies may average sustained winds over one, three, or ten minutes, so identical-looking knot values are not always directly comparable across ocean basins.