Use this sailing calculation as a planning or educational cross-check for navigation, wind and current, rig loads, stability, anchoring, tides, visibility, performance, or recovery under explicitly stated conditions.

Relative humidity (%)

Relative humidity of the air.

Air temperature (°C)

Dry bulb air temperature in degrees Celsius.

Wind speed (m/s)

Wind speed at the observer; stronger wind lowers the result.

Compute the simplified apparent temperature from air temperature, humidity-derived vapour pressure, and wind speed. With wind omitted, the result represents still air. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Apparent temperature (°C)

Apparent temperature combining heat and humidity stress.

• Actual conditions change with vessel design and loading, sea state, wind, current, tide datum, weather, chart accuracy, equipment, crew, regulations, and safety margins. Simplified formulas do not replace seamanship, approved stability data, or current navigation information.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Cross-check official charts, tide and weather services, instrument data, vessel manuals, and collision regulations; maintain conservative margins and a safe alternative plan.

• Wind Pressure on Sail Calculator

  Compute aerodynamic force on a sail from dynamic pressure using 0.5 times air density times wind speed squared times sail area times lift coefficient.

• Apparent Wind Angle Calculator

  Compute the apparent wind angle from true wind speed, boat speed, and true wind angle.

• Apparent Wind Speed Calculator

  Compute the apparent wind speed from true wind speed, boat speed, and true wind angle.