What is a Windsock?

Windsocks are tube-shaped devices resembling flags, providing information on both wind direction and intensity. Widely used in aviation, maritime navigation, and industrial settings, they offer quick insights into weather conditions.

Reading a Windsock:

To interpret a windsock:

  1. Observe the windsock and align yourself for a clear view.
  2. Count the upright segments (bands) of the windsock, denoted as ‘n.’
  3. To estimate wind speed in knots, use the formula: wind speed [knots] = n × 3.

Windsock Standards:

In aviation, windsocks follow specific standards set by organizations like the FAA. Common measurements include a length of 3.60m (12ft) or 2.50m (8ft) and a diameter of 0.9m (36in) or 0.45m (18in) at the large end. They typically hang 4.8m (15.7ft) above the ground.

Windsock Calculator:

Utilize our windsock calculator by inputting the number of upright segments. The tool then provides wind speed in knots, metric, and imperial units.

Wind Speed Approximation:

While windsocks aren’t precise instruments, they offer a rough indication of wind intensity. As the wind speed increases, the windsock becomes more upright. The relationship between wind speed in knots and upright segments is given by wind speed [knots] = 3 × n segments.

Possible Wind Speeds:

  • 1 segment: ≤3 knots (≤5.6 km/h, ≤3.5 mph, ≤1.5 m/s)
  • 2 segments: 6 knots (11.1 km/h, 6.9 mph, 3.1 m/s)
  • 3 segments: 9 knots (16.7 km/h, 10.4 mph, 4.6 m/s)
  • 4 segments: 12 knots (22.2 km/h, 13.8 mph, 6.2 m/s)
  • 5 segments: 15+ knots (27.8+ km/h, 17.3+ mph, 7.7+ m/s)


  • Reading a Windsock: Align, count segments, and use the formula.
  • Windsock Extension: Fully extended for ≥15 knots.
  • How it Works: Aerodynamics compresses wind in the larger end, making it upright.
  • Invention: Windsocks date back to ancient times, gaining modern form in the 19th century.

Explore further: Check out our wind chill calculator for temperature considerations.

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