Calculate the wind speed in knots. Access a weather website to view your area's temperature and wind speed in knots.
Calculate the apparent wind of the boat. The wind equals the square root of "sine (the true wind angle) x (the true wind speed) squared." Add this by the "boat's speed +cosine (the true wind angle) x (the true wind speed) squared." The true-wind angle equals "90 -- arctangent x the boat's speed divided by the true wind."
Subtract the heading of the boat and the wind's direction. Check to see the direction of the boat and the wind by configuring a directional wheel. For example, a boat traveling north is traveling at zero degrees while wind traveling south is traveling at 180 degrees.
Press the "Calculate" button to view the difference between the heading and the true wind direction. Complete by adding the heading, found in step three, to the solution to get the true wind direction. Check the directional wheel again and compare your degrees to see the actual direction of the true wind.
