Watch the video above to see how to find the wind speed by using a flag.

There are two ways that you can use a flag to find the wind speed.

The easiest way is to just look at the flag and get a rough idea of the wind by using these simple steps.

• If the flag is not moving, the wind is calm and below 11 mph.
• If the flag flaps lightly, the wind speed is between 12 to 18 mph.
• If the flag is waving over the entire length, the wind speed is 19 to 24 mph.
• If the flag is stretched and flapping fast, the wind speed is 25 to 31 mph.
• If the flag is stretched and flapping hard, the wind speed is 32 to 37 mph.

The harder way is to use the “Math Way.” The steps to do this are below.

Use the flag pole. Take the angle of the flag in relation to the flag pole and divide that angle by the number 4. The answer will give you the wind speed in miles per hour.

*ANGLE OF FLAG / 4 = WIND SPEED in MPH

Examples:
If flag is down on the pole, the angle would be 0°.
0 / 4 = 0 mph
If flag is out at 45° off the pole.
45 / 4 = 11.25 mph (around 11 mph)
If flag is straight out at 90° off the pole.
90 / 4 = 22.5 (around 20 mph)

Below is a list of most of the angles and their wind speed.
90° 90 / 4 = 22.5 mph
80° 80 / 4 = 20.0 mph
70° 70 / 4 = 17.5 mph
60° 60 / 4 = 15.0 mph
50° 50 / 4 = 12.5 mph
40° 40 / 4 = 10.0 mph
30° 30 / 4 = 7.0 mph
20° 20 / 4 = 5.0 mph
10° 10 / 4 = 6.25 mph
0° 0 / 4 = 0.0 mph (CALM)