A Frostbite Calculator is a public health and safety tool that estimates the risk of developing frostbite on exposed skin by calculating the Wind Chill Temperature. Frostbite is a serious medical condition where body tissues freeze, causing damage. The risk of frostbite depends not just on the air temperature, but also on the wind speed, as wind dramatically increases the rate at which your body loses heat. This calculator uses the official Wind Chill formula, developed by meteorological services, to determine how cold the air "feels" on your skin. Based on this calculated wind chill value, it then provides an estimated time until frostbite can occur, serving as a crucial warning for anyone planning to be outdoors in cold and windy conditions.
formula of Frostbite Calculator
The calculation is a two-step process. First, the Wind Chill Temperature is calculated. Second, that result is used to estimate the time to frostbite.
1. Wind Chill Temperature Calculation
This formula, developed by the National Weather Service (U.S.) and Environment Canada, is the standard for calculating wind chill.
Formula for Fahrenheit (°F) and Miles Per Hour (MPH)
Use this formula when your inputs are in Imperial units.
Wind Chill (°F) = 35.74 + (0.6215 * T) - (35.75 * (V^0.16)) + (0.4275 * T * (V^0.16))
- T: The actual air temperature in degrees Fahrenheit (°F).
- V: The wind speed in Miles Per Hour (MPH).
- ^0.16: The exponent operator ("to the power of 0.16").
Formula for Celsius (°C) and Kilometers Per Hour (km/h)
Use this formula when your inputs are in Metric units.
Wind Chill (°C) = 13.12 + (0.6215 * T) - (11.37 * (V^0.16)) + (0.3965 * T * (V^0.16))
- T: The actual air temperature in degrees Celsius (°C).
- V: The wind speed in Kilometers Per Hour (km/h).
- ^0.16: The exponent operator ("to the power of 0.16").
2. Estimated Time to Frostbite Based on Wind Chill
This is not a formula but a set of thresholds. Once you have the Wind Chill value, you can determine the risk level.
| Wind Chill Temperature (°F) | Wind Chill Temperature (°C) | Risk of Frostbite for Exposed Skin |
| Above +14°F | Above -10°C | Low Risk |
| +13°F to -12°F | -10°C to -24°C | Caution: Increasing risk |
| -13°F to -30°F | -25°C to -34°C | Warning: Frostbite possible in 10 to 30 minutes |
| -31°F to -50°F | -35°C to -45°C | Warning: Frostbite possible in 5 to 10 minutes |
| -51°F to -75°F | -46°C to -60°C | Extreme Warning: Frostbite possible in 2 to 5 minutes |
| Below -75°F | Below -60°C | Extreme Danger: Frostbite possible in under 2 minutes |
Wind Chill Chart (°F)
This table provides a quick reference for the calculated wind chill temperature based on various air temperatures and wind speeds.
| Temp (°F) / Wind (MPH) | 5 | 10 | 15 | 20 | 30 | 40 |
| 30°F | 25°F | 21°F | 19°F | 17°F | 15°F | 13°F |
| 20°F | 13°F | 9°F | 6°F | 4°F | 1°F | -1°F |
| 10°F | 1°F | -4°F | -7°F | -9°F | -12°F | -14°F |
| 0°F | -11°F | -16°F | -19°F | -22°F | -25°F | -27°F |
| -10°F | -22°F | -28°F | -32°F | -35°F | -38°F | -40°F |
| -20°F | -34°F | -40°F | -44°F | -47°F | -51°F | -53°F |
Example of Frostbite Calculator
Let's calculate the wind chill and frostbite risk for a day with the following weather conditions.
First, we identify the conditions.
- Air Temperature (T): -10°F
- Wind Speed (V): 20 MPH
Step 1: Use the Wind Chill formula for Fahrenheit.
Wind Chill (°F) = 35.74 + (0.6215 * T) - (35.75 * (V^0.16)) + (0.4275 * T * (V^0.16))
Wind Chill (°F) = 35.74 + (0.6215 * -10) - (35.75 * (20^0.16)) + (0.4275 * -10 * (20^0.16))
First, calculate 20^0.16 ≈ 1.644
Wind Chill (°F) = 35.74 + (-6.215) - (35.75 * 1.644) + (-4.275 * 1.644)
Wind Chill (°F) = 35.74 - 6.215 - 58.785 + (-7.058) ≈ -36°F
Step 2: Determine the frostbite risk from the calculated wind chill.
A wind chill of -36°F falls into the "-31°F to -50°F" category.
Therefore, under these conditions, the "feels like" temperature is approximately -36°F, and there is a warning that frostbite is possible on exposed skin in just 5 to 10 minutes.
Most Common FAQs
Wind chill is a measure of the rate of heat loss from the human body due to the combined effects of wind and cold air temperature. It is not the actual temperature of the air; rather, it is an expression of how cold the air "feels" on exposed skin. Wind accelerates heat loss by stripping away the thin layer of warm air that insulates the body.
The first signs of frostbite, sometimes called "frostnip," include a "pins and needles" feeling, followed by numbness or tingling in the affected area. The skin may appear white, pale, or grayish and may feel hard or waxy to the touch. If you experience these symptoms, you should get out of the cold immediately and slowly rewarm the affected area.
No. This calculator is a safety and informational tool based on meteorological data to help you understand the risks of cold weather. It is not a medical diagnostic tool. If you believe you or someone else has frostbite, you should seek immediate medical attention.