““Wind flags can be used to estimate wind speed by their angle. If a flag is at an 80-degree angle, that number is divided by the constant 4—to get 20 miles per hour. Likewise, if the flag only waves at a 40-degree angle, 40 divided by 4 equals 10 miles per hour. If no flag is available, the sniper can use his observation skills. A wind that is barely felt but causes smoke to drift is less than 3 miles per hour. Light winds are 3 to 5 miles per hour. Wind that constantly blows leaves around is 5 to 8 miles per hour. Dust and trash are blown at 8 to 12 miles per hour. Trees sway at 12 to 15 miles per hour. A””
