Wind Chill Chart: When Cold Becomes Dangerous

To read a wind chill chart, find the air temperature along the top row and the wind speed down the left column. The number where they meet is the wind chill, which is how cold the weather feels on exposed skin. The National Weather Service (NWS) gives this example: “If the temperature is 0°F and the wind is blowing at 15 mph, the wind chill is -19°F. At this wind chill temperature, exposed skin can freeze in 30 minutes.”

The chart below is the NWS chart, rewritten as a table so you can read it on a phone and copy it. It only works for certain conditions. The NWS says the wind chill temperature “is defined only for temperatures at or below 50°F and wind speeds above 3 mph.” Local forecasts and local emergency officials come first. This page gathers what the NWS and the CDC say. It is a reference, not a forecast and not medical advice.

Source: National Weather Service, Understanding Wind Chill (weather.gov), accessed November 2026.

NWS wind chill chart

Each cell is the wind chill in °F. Air temperature runs across the top and wind speed in miles per hour runs down the side.

Source: National Weather Service, Wind Chill Chart, shown on Understanding Wind Chill (weather.gov), accessed November 2026. Values were transcribed from the NWS chart and checked cell by cell against the NWS formula.

To use it, pick the column for today’s air temperature, then move down to the row for the wind. At 20°F with a 20 mph wind, the chart says 4, so it feels like 4°F on bare skin. At 10°F with a 30 mph wind it says -12. At -10°F with a 25 mph wind it says -37.

If the wind falls between two rows, such as 22 mph, read the closest row. The formula further down gives an exact figure for any wind speed.

When does frostbite start? The 30, 10 and 5 minute bands

The NWS chart is shaded. Its legend labels three bands under the heading “Frostbite Times”: 30 minutes, 10 minutes and 5 minutes. Cells without any shading, the warmer part of the chart, carry no frostbite time on the NWS chart. Moving right and down, the chart reaches the 30 minute band first, then the 10 minute band, then the 5 minute band.

The second table shows where each band begins on each wind speed row. It lists the first air temperature on the chart where that shading appears, along with the wind chill value printed in that cell.

Source: National Weather Service, Wind Chill Chart, shown on Understanding Wind Chill (weather.gov), accessed November 2026. The band start points were read from the shading of the NWS chart image, so check any cell you rely on against the chart on weather.gov.

The bands are not set by one wind chill number. At 5 mph the 30 minute band does not begin until the air is -10°F, but at 60 mph it begins at 10°F. Strong wind moves the danger zone into much milder air.

Frostbite is not only a chart number. The NWS says it is most likely on fingers, toes, nose and ears, and can affect any area of exposed skin. It also notes that the wind chill tests “were conducted on adult subjects,” and the NWS says to “use the existing chart as a starting point and be even more cautious with children, the elderly, and persons with compromised health.”

Source: National Weather Service, Understanding Wind Chill (weather.gov), accessed November 2026.

How the wind chill formula works

The NWS publishes the calculation behind the chart:

“Wind chill (ºF) = 35.74 + 0.6215T - 35.75(V^0.16) + 0.4275T(V^0.16)”

“T = Air Temperature (F)” and “V = Wind Speed (mph)”. The caret means “raised to a power”.

Here it is with the NWS example. At 0°F and 15 mph, 15 raised to the 0.16 power is about 1.542. That gives 35.74 minus 35.75 times 1.542, which is about -19.4, and the chart rounds it to -19. A scientific calculator or a spreadsheet handles the power step if you want to try your own numbers.

The NWS says the index calculates wind speed at about 5 feet, “the typical height of an adult human face,” from readings taken at 33 feet. It assumes no effect from the sun, so a clear night sky, and it sets the calm wind cutoff at 3 mph. The NWS also reports that humidity changed the result by less than one degree in its tests, so humidity is left out.

Source: National Weather Service, Understanding Wind Chill (weather.gov), accessed November 2026.

What a wind chill chart does not tell you

It does not apply to pipes or your car. The NWS says “the only effect wind chill has on inanimate objects, such as car radiators and water pipes, is to cool the object more quickly to the current air temperature.” It adds “The inanimate object will NOT cool below the actual air temperature.” A pipe freezes because of the air temperature, so the wind chill number tells you little about your pipes. The frozen pipes guide covers what to do before a hard freeze.

It does not mean frostbite is possible above freezing. The NWS says “The air temperature has to be BELOW freezing for frostbite to develop on exposed skin.” Wind chill cannot push skin below the air temperature. Hypothermia is a different matter: the CDC says it can occur even at cool temperatures, above 40°F, if a person gets chilled from rain, sweat or cold water.

It assumes shade. The NWS says “Bright sunshine may increase the wind chill temperature by 10°F to 18°F.” Sun on your face helps, but the sun does not change the air temperature, and you lose that help the moment you step into shade or the sun goes down.

It was tested on adults. The extra caution the NWS asks for with children, older adults and anyone with health problems is easy to skip when the number looks tolerable.

It is not the same as an alert threshold. The NWS says “Cold is dangerous with or without wind,” and alert criteria differ from place to place, which the next section explains.

Source: National Weather Service, Understanding Wind Chill (weather.gov), accessed November 2026.

What NWS cold alerts mean

The NWS uses three cold alerts. Its page on cold weather alerts describes them this way.

• Extreme Cold Warning, “Take Action!” “An Extreme Cold Warning is issued when extremely dangerous cold conditions or wind chill values are expected or occurring. If you are in an area with an Extreme Cold Warning, avoid going outside. If you have to go outside, dress in layers, cover exposed skin, and make sure at least one other person knows your whereabouts. Update them when you arrive safely at your destination.”
• Extreme Cold Watch, “Be Prepared.” An Extreme Cold Watch is issued when extremely dangerous cold conditions or wind chill values are “possible, but the occurrence, location, and/or timing is still uncertain.” The NWS tells people to “Make sure your car has at least half a tank of gas, and update your winter survival kit.”
• Cold Weather Advisory, “Be Aware.” “A Cold Weather Advisory is issued for dangerously cold conditions that are not expected to reach warning criteria. Be sure you and your loved ones dress appropriately and cover exposed skin when venturing outdoors.”

Source: National Weather Service, Understanding Cold Weather Alerts (weather.gov), accessed November 2026.

You may still see older “wind chill advisory” and “wind chill warning” wording on old articles and some weather pages. The current NWS names are the ones above.

There is no single wind chill number that triggers an alert everywhere. The NWS says “Criteria for issuing official NWS Extreme Cold Warnings and Cold Weather Advisories are set locally.” As one example, it says the Rochester, New York area uses these numbers: “Extreme Cold Warnings are issued when the apparent temperature with or without wind is expected to fall at or below -25°F” and “Cold Weather Advisories are issued when the air temperature or wind chill temperature is expected to fall between -15°F and -24°F.” Your own NWS office will use thresholds that fit your climate, so check its forecast page at weather.gov and follow what your local officials say.

Source: National Weather Service, Understanding Wind Chill (weather.gov), accessed November 2026.

Signs of frostbite and hypothermia

These are the CDC’s warning signs. They are worth knowing even when the chart number looks tolerable, because the chart is an estimate built on tests with adults.

Frostbite. The CDC says: “Redness or pain in any skin area may be the first sign of frostbite.” Other signs it lists are:

• “A white or grayish-yellow skin area”
• “Skin that feels unusually firm or waxy”
• “Numbness”

The CDC also says “A victim is often unaware of frostbite because frozen tissue is numb,” so check each other’s faces, ears and noses. Its guidance includes “Seek medical attention as soon as possible” and “Do not rub or massage areas with frostbite.”

Source: CDC, Preventing Frostbite (cdc.gov), accessed November 2026.

Hypothermia. For adults, the CDC lists these warning signs: “Shivering,” “Exhaustion or feeling very tired,” “Confusion,” “Fumbling hands,” “Memory loss,” “Slurred speech” and “Drowsiness.” For babies it lists “Bright red, cold skin” and “Very low energy.” It says: “If a person’s temperature is below 95 degrees get medical attention immediately.”

Source: CDC, Preventing Hypothermia (cdc.gov), accessed November 2026.

If you think someone has frostbite or hypothermia, call 911 or your local emergency number. When in doubt, get medical help. This page is not medical advice.

What to do when the wind chill is dangerous

The NWS says to avoid going outside during an Extreme Cold Warning. If you have to go out, its advice for extreme cold is to dress in layers. It adds: “Cover exposed skin to reduce your risk of frostbite or hypothermia. Try to seek shelter from the wind as much as possible while outside.” It also says “Mittens are better than gloves. Keep your skin dry. Stay out of the wind when possible.”

Source: National Weather Service, During Extremely Cold Weather (weather.gov), accessed November 2026.

A few practical notes that fit those steps:

• Cover the parts the chart worries about. Fingers, toes, nose and ears are the usual trouble spots, so a hat, a face covering and mittens matter. Hand warmers are one more option for your hands and feet. Our hand warmer comparison lays out the published specs and safety notes. We did not test any of them.
• Tell someone your route. The NWS suggests making sure at least one other person knows where you are going, then updating them when you arrive.
• Plan for the car. Keep at least half a tank of gas in extreme cold and update your winter survival kit, as the NWS advises. Our winter car kit guide lists what to carry, and the car kit gear section shows the matching items.
• Have a warm plan if the power goes out. A cold snap and an outage can overlap. See how to stay warm without power for safe ways to heat one room and layer up, and the emergency kit section of the resources page for blankets and a first aid kit.
• Get ahead of a bigger storm. If the cold comes with snow or ice, how to prepare for a winter storm covers supplies, fuel and pipes, and the free printable at the end of this page puts the steps on paper.

Wind chill chart FAQ

What wind chill is dangerous? The NWS does not give one number for everyone. Its anchor example is -19°F, where exposed skin can freeze in 30 minutes, and its alert thresholds are set locally. Cold can be dangerous with or without wind.

Does wind chill affect pipes, cars or pets? It applies to people and animals. It does not cool pipes or car radiators below the air temperature. The NWS tells pet and livestock owners to make sure animals “are not overly exposed to extreme cold” and have food and water that has not frozen.

Can I get frostbite above freezing? The NWS says no. The air temperature has to be below freezing for frostbite to develop on exposed skin, although hypothermia can still happen.

Does the chart work for kids? It was tested on adults. The NWS says to use it as a starting point and be even more cautious with children.

Sources for this FAQ: National Weather Service, Understanding Wind Chill and Prepare for Cold Weather (weather.gov), accessed November 2026.