Wind Chill Chart Table
| Air °F ↓ / Wind mph → | 5 | 10 | 15 | 20 | 25 | 30 | 35 | 40 | 45 | 50 | 55 | 60 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 40 | 36 | 34 | 32 | 30 | 29 | 28 | 28 | 27 | 26 | 26 | 25 | 25 |
| 35 | 31 | 27 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 19 | 18 | 17 |
| 30 | 25 | 21 | 19 | 17 | 16 | 15 | 14 | 13 | 12 | 12 | 11 | 10 |
| 25 | 19 | 15 | 13 | 11 | 9 | 8 | 7 | 6 | 5 | 4 | 4 | 3 |
| 20 | 13 | 9 | 6 | 4 | 3 | 1 | 0 | -1 | -2 | -3 | -3 | -4 |
| 15 | 7 | 3 | 0 | -2 | -4 | -5 | -7 | -8 | -9 | -10 | -11 | -11 |
| 10 | 1 | -4 | -7 | -9 | -11 | -12 | -14 | -15 | -16 | -17 | -18 | -19 |
| 5 | -5 | -10 | -13 | -15 | -17 | -19 | -21 | -22 | -23 | -24 | -25 | -26 |
| 0 | -11 | -16 | -19 | -22 | -24 | -26 | -27 | -29 | -30 | -31 | -32 | -33 |
| -5 | -16 | -22 | -26 | -29 | -31 | -33 | -34 | -36 | -37 | -38 | -39 | -40 |
| -10 | -22 | -28 | -32 | -35 | -37 | -39 | -41 | -43 | -44 | -45 | -46 | -48 |
| -15 | -28 | -35 | -39 | -42 | -44 | -46 | -48 | -50 | -51 | -52 | -54 | -55 |
| -20 | -34 | -41 | -45 | -48 | -51 | -53 | -55 | -57 | -58 | -60 | -61 | -62 |
| -25 | -40 | -47 | -51 | -55 | -58 | -60 | -62 | -64 | -65 | -67 | -68 | -69 |
| -30 | -46 | -53 | -58 | -61 | -64 | -67 | -69 | -71 | -72 | -74 | -75 | -76 |
| -35 | -52 | -59 | -64 | -68 | -71 | -73 | -76 | -78 | -79 | -81 | -82 | -84 |
| -40 | -57 | -66 | -71 | -74 | -78 | -80 | -82 | -84 | -86 | -88 | -89 | -91 |
| -45 | -63 | -72 | -77 | -81 | -84 | -87 | -89 | -91 | -93 | -95 | -97 | -98 |
Wind chill is what the air does to exposed skin once wind starts stripping away the warm boundary layer your body maintains. The NWS formula behind the chart below is Wind chill = 35.74 + 0.6215T - 35.75(V^0.16) + 0.4275T(V^0.16), and it is only defined at air temperatures of 50F or below and wind speeds above 3 mph - in calmer air the reading simply equals the air temperature. Every one of the 216 cells in the matrix is regenerated directly from that formula and cross-checked against the NWS's own example: 0F air with a 15 mph wind reads -19F.
The index was rebuilt in 2001 by NWS and Environment Canada using human-subject wind-tunnel trials, and it assumes wind measured at an average height of 5 feet - roughly an adult face - rather than airport anemometer height. That face-height assumption is why the chart reads colder than older charts from the same weather.
How to use
- Find your air temperature row (top row 40F down to -45F) and your wind speed column (5 to 60 mph); the cell is the feels-like temperature.
- Type temp and wind into the reader above to snap to the nearest chart cell instantly - it flags any reading of -18F or colder, where NWS says exposed skin can freeze in about 30 minutes.
- Remember the two honest caveats: bright sunshine raises the effective reading by 10-18F, and wind chill never cools water or pipes below the actual air temperature.
Frequently asked questions
What wind chill is dangerous for frostbite?
NWS states that at a wind chill of -18F, exposed skin can freeze in about 30 minutes - their example: a 5F day with a 30 mph wind reads -19F. The official printed chart adds darker bands for 10-minute and 5-minute frostbite times at colder, windier combinations. Below roughly -50F readings, frostbite times drop to minutes, which is why Extreme Cold Warnings carry skin-exposure language.
Can wind chill freeze my pipes or car radiator?
No - and this is the most misunderstood point about the index. Wind chill measures how fast living skin loses heat; it cannot cool an object below the actual air temperature. Water freezes at 32F whether the wind chill reads +20F or -40F. Pipes burst in cold snaps because air temperature fell below freezing, not because of the wind chill number - insulating for wind still helps by stripping away warmed air at the pipe surface.
Why is wind chill only defined at or below 50F and above 3 mph?
Those are the bounds of the science, stated verbatim in the NWS definition: the index is only defined for temperatures at or below 50F and wind speeds above 3 mph. Below the wind floor, human walking speed generates its own airflow, so a calm-air reading would be arbitrary - and the NWS treats calm wind as simply the air temperature. Above 50F the heat-stress problem inverts, which is where heat index takes over.
Does sunshine change the wind chill reading?
Yes, and NWS says so on the chart page: bright sunshine may increase the wind chill temperature by 10F to 18F. The published chart assumes shade, which is one reason skiers report feeling far warmer than the number - and why the same cell can feel two ways on the same afternoon.