Wind Chill Calculator · Practical guide
What Is the Wind Chill at 20 Degrees and 15 MPH Wind?
20°F air with a 15 mph wind feels like 6.2°F on exposed skin — cold, but below the frostbite thresholds.
At a glance
The Answer: About 6.2°F
Plug 20°F and 15 mph into the North American wind chill formula and the perceived temperature is 6.2°F. Frostbite risk at that level is low — the 30-minute frostbite zone does not begin until the wind chill reaches −19°F. You still want a hat and gloves, but a normal winter outing is fine.
Interactive tool
Wind Chill Calculator
Enter your own values, then compare the result with the examples below.
Wind Chill Results
The Math Behind It
The formula is 35.74 + 0.6215T − 35.75V^0.16 + 0.4275TV^0.16, where T is air temperature in °F and V is wind speed in mph:
- 15^0.16 = 1.5424
- 35.74 + 0.6215 × 20 = 48.17
- −35.75 × 1.5424 = −55.14
- +0.4275 × 20 × 1.5424 = +13.19
- Total: 48.17 − 55.14 + 13.19 = 6.2°F
How 20°F Feels at Other Wind Speeds
| Wind speed | Wind chill at 20°F | Frostbite risk |
|---|---|---|
| 5 mph | 13.0°F | Low |
| 15 mph | 6.2°F | Low |
| 25 mph | 2.6°F | Low |
| 35 mph | 0.1°F | Low |
| 45 mph | −1.8°F | Low |
Even at 45 mph, 20°F air only chills to about 0°F — comfortably above the −19°F frostbite threshold. Wind chill at 20°F becomes genuinely dangerous only in extreme gusts, which is rare; the real danger zone starts when the air itself drops near or below 0°F.
A Note on the Formula's Limits
The wind chill index applies only at or below 50°F and at wind speeds of 3 mph or more. Below 3 mph the calculator shows a note instead of a number, because at near-calm conditions the air and the perceived temperature are effectively the same.
Frequently Asked Questions
Is 20°F with 15 mph wind dangerous?
Not for healthy, properly dressed adults — the wind chill is about 6.2°F, well above the −19°F level where frostbite becomes a 30-minute risk. Cover extremities and limit prolonged exposure.
How much colder does 15 mph wind make it feel?
At 20°F, a 15 mph wind removes enough heat to make it feel about 14 degrees colder — 6.2°F instead of 20°F. The gap grows as air temperature falls.
What wind chill would 20°F need to reach the frostbite zone?
The wind chill would have to hit −19°F. At 20°F air temperature, no realistic sustained wind speed gets there — even 60 mph only reaches about −4.2°F.
Does 6°F wind chill freeze pipes or cars?
No. Wind chill affects only living tissue and perceived cold. Inanimate objects cool no lower than the actual air temperature of 20°F — they just reach it faster.