Wind Chill Calculator
An expert tool to determine the ‘feels like’ temperature based on the two key factors: air temperature and wind speed.
Enter the ambient air temperature.
Enter the sustained wind speed.
Wind Chill / ‘Feels Like’ Temperature
Calculation based on the North American formula.
Wind Chill vs. Wind Speed
What is the Wind Chill Factor?
The **wind chill factor** is not the actual air temperature, but rather a measure of how cold it feels on exposed skin due to the combined effects of the two primary considerations: **air temperature and wind speed**. When wind blows across the skin, it removes the thin layer of warm air that surrounds our body, causing heat loss to accelerate. This makes the environment feel much colder than the thermometer reading. Understanding the **which two considerations are used to calculate a windchill factor** is crucial for safety in cold weather to prevent conditions like frostbite and hypothermia.
This calculator is used by anyone who will be spending time outdoors in cold, windy conditions, including outdoor workers, winter sports enthusiasts, and emergency responders. A common misunderstanding is that wind chill affects inanimate objects; however, it only affects the rate at which they cool. An object will not cool below the actual air temperature.
The Two Factors & The Wind Chill Formula
The modern wind chill formula was developed by a joint effort between Canadian and US scientists and is calculated using only two key variables: air temperature and wind speed. The formula varies depending on the units used.
Formula for Fahrenheit (°F) and Miles per Hour (mph)
This is the standard formula used by the U.S. National Weather Service.
Wind Chill (°F) = 35.74 + 0.6215*T - 35.75*(V^0.16) + 0.4275*T*(V^0.16)
Formula for Celsius (°C) and Kilometers per Hour (km/h)
This is the standard formula used by Environment Canada.
Wind Chill (°C) = 13.12 + 0.6215*T - 11.37*(V^0.16) + 0.3965*T*(V^0.16)
| Variable | Meaning | Unit (auto-inferred) | Typical Range |
|---|---|---|---|
| T | Air Temperature | °F or °C | -50°F to 50°F (-45°C to 10°C) |
| V | Wind Speed | mph or km/h | 3 mph to 100 mph (5 km/h to 160 km/h) |
Learn more about Extreme Weather Safety to stay prepared.
Practical Examples
Example 1: A Cold Day in Chicago
- Inputs: Air Temperature = 10°F, Wind Speed = 20 mph
- Units: Imperial (Fahrenheit, mph)
- Results: The wind chill would be approximately -9°F. This significantly increases the risk of frostbite on exposed skin.
Example 2: A Winter Hike in the Rockies
- Inputs: Air Temperature = -15°C, Wind Speed = 30 km/h
- Units: Metric (Celsius, km/h)
- Results: The wind chill would be approximately -28°C. At this level, exposed skin can freeze in under 10-30 minutes.
How to Use This Wind Chill Factor Calculator
- Enter Air Temperature: Input the current ambient air temperature into the first field.
- Select Temperature Unit: Choose whether you are using Fahrenheit (°F) or Celsius (°C). The calculator defaults to Fahrenheit.
- Enter Wind Speed: Input the sustained wind speed. The formula is most accurate for speeds above 3 mph (5 km/h).
- Select Speed Unit: Choose between Miles per Hour (mph) or Kilometers per Hour (km/h).
- Interpret Results: The calculator instantly displays the wind chill temperature. Pay attention to the frostbite warnings provided. Check our guide on Dressing for Cold Weather for tips.
Key Factors That Affect Wind Chill
- Air Temperature: This is the most critical factor. The colder the air, the more significant the impact of wind.
- Wind Speed: The second primary factor. Higher wind speeds accelerate heat loss from the body.
- Exposure Time: The longer you are exposed, the more heat your body loses, increasing the risk of hypothermia.
- Sunshine: Bright sunshine can make the wind chill feel 10°F to 18°F warmer, but the official formula assumes no sun (clear night sky).
- Humidity: While not a direct factor in the wind chill formula, high humidity can make it feel colder as moisture on the skin evaporates and cools the body.
- Personal Factors: Your clothing, metabolism, and whether you are wet or dry all influence how cold you actually feel. Understanding Hypothermia is essential.
Wind Chill Reference Table
Frequently Asked Questions (FAQ)
What are the two considerations used to calculate a windchill factor?
The two considerations are air temperature and wind speed. No other factors are used in the official formula.
Is wind chill the actual temperature?
No, it is a “feels like” temperature. It represents the increased rate of heat loss from exposed skin, not the actual air temperature. An object’s temperature will not drop below the ambient air temperature due to wind chill.
Why doesn’t the calculator work for temperatures above 50°F / 10°C?
The wind chill effect is only defined for cold temperatures where it poses a risk to human health. At warmer temperatures, wind can have a pleasant cooling effect.
At what wind speed is wind chill calculated?
The formula is valid for wind speeds above 3 mph (about 5 km/h). Below this speed, the effect is negligible.
Can wind chill freeze my car’s engine coolant?
No. The wind chill cannot cool an object to a temperature below the actual air temperature. If your coolant is rated for -30°F, it will not freeze unless the air temperature itself drops to -30°F, regardless of the wind speed.
How is the wind speed measured for the formula?
The official formula uses wind speed measured at a standard height of 33 feet (10 meters) and then adjusts it to the average height of a human face (5 feet), where the cooling is most felt. For more on weather measurement, see our guide on Home Weather Stations.
Does this calculator work for both Fahrenheit and Celsius?
Yes. You can select your preferred units for temperature (°F or °C) and wind speed (mph or km/h), and the calculator will use the correct formula automatically.
What is frostbite and when does it occur?
Frostbite is an injury caused by the freezing of skin and underlying tissues. The risk becomes significant at wind chills below -18°F (-28°C), where it can occur in under 30 minutes. Our First Aid for Frostbite page has more details.
Related Tools and Internal Resources
- Heat Index Calculator: Calculate the “feels like” temperature in hot and humid conditions.
- Dew Point Calculator: Understand how humidity relates to comfort and temperature.