OSHA’s cold weather chart is a wind chill grid, adapted from the National Weather Service, that lets an employer combine air temperature and wind speed into a single “feels like” value and a frostbite-onset time for exposed skin.1Occupational Safety and Health Administration. Winter Weather – Cold Stress Those two numbers drive the practical decisions on a cold-weather job: what workers wear, how long they can stay outside between warm-up breaks, and when non-emergency work should stop. OSHA has no standalone cold-weather standard, but the General Duty Clause of the OSH Act still requires every workplace to be free from recognized hazards likely to cause death or serious physical harm, and cold stress qualifies.2Occupational Safety and Health Administration. OSH Act of 1970 – Section 5 Duties
How to Read the Chart
The chart is a grid. Air temperature runs along one axis, wind speed along the other. Find the current temperature, follow the row to the current wind speed, and the cell where they meet gives you the wind chill value. Colored bands across the chart mark how quickly frostbite can develop on exposed skin at that wind chill.3Occupational Safety and Health Administration. Wind Chill Chart
The National Weather Service divides frostbite onset into three time bands: 30 minutes, 10 minutes, and 5 minutes.4National Weather Service. Wind Chill Chart A wind chill of -20°F puts bare skin in the 30-minute zone. At -45°F wind chill, frostbite can begin in as little as 5 minutes. Those times assume exposed skin, so proper clothing extends the window, which is why the chart works together with clothing and scheduling decisions rather than standing alone.
Why Wind Chill, Not Air Temperature
Air temperature alone underestimates the hazard. Wind strips away the thin layer of warm air that normally insulates the skin, so the faster the wind blows, the faster the body loses heat. Wind chill captures that combined effect in a single number.1Occupational Safety and Health Administration. Winter Weather – Cold Stress
The gap matters. An air temperature of 40°F combined with a 35 mph wind produces a wind chill of 28°F: exposed skin loses heat as though the air were 12 degrees colder than the thermometer reads.5National Weather Service. Wind Chill Chart An employer planning breaks and gear around the thermometer alone will consistently under-protect the crew. Wet conditions worsen this further; cold stress injuries can develop at air temperatures as high as 60°F when workers are standing in cold water or wearing soaked clothing.
Turning a Chart Reading Into a Work-Rest Schedule
Once you have a wind chill value, the chart feeds into scheduling. The American Conference of Governmental Industrial Hygienists publishes work-to-rest ratios that many employers pair with OSHA’s chart. The published schedule assumes moderate-to-heavy physical work over a four-hour shift, with 10-minute warm-up breaks in a heated area, and workers in dry clothing.
- At -20°F with no significant wind, normal breaks (one every two hours) are sufficient.
- At -20°F with a 10 mph wind, work periods drop to a maximum of 55 minutes, with three warm-up breaks per four-hour shift.
- At -20°F with a 20 mph wind, work periods drop again to 30 minutes, with five warm-up breaks per shift.
- At -25°F with a 15 mph wind or worse, non-emergency outdoor work should stop entirely.
Lighter physical work shifts the schedule one level more restrictive, because a worker moving less generates less body heat. Wet clothing demands more caution still.
What the Chart Tells You to Do Next
OSHA expects a layered response to cold stress: change the environment first, then adjust work practices, and provide proper gear.
Environmental Changes
Radiant heaters near work zones or break areas, wind shields, and temporary enclosures reduce effective wind chill even when the air temperature stays the same. Cold storage and freezer operations benefit from insulated flooring and heated break rooms placed immediately adjacent to work areas so workers aren’t shocked crossing between zones.
Work Practices
Short, frequent warm-up breaks in a heated dry area, timed to the wind chill level and work intensity, are the core administrative control. Schedule the most physically demanding tasks for the warmest part of the day. Use a buddy system, because a worker developing hypothermia often doesn’t recognize their own confusion. Provide warm, sweetened drinks; avoid alcohol entirely and limit caffeine, since both impair temperature regulation. Train workers before cold-weather work begins on recognizing conditions and symptoms, selecting clothing, and giving correct first aid.1Occupational Safety and Health Administration. Winter Weather – Cold Stress
Clothing
OSHA’s cold stress guide recommends at least three loose-fitting layers, because tight clothing restricts blood flow to the extremities.6Occupational Safety and Health Administration. Cold Stress Guide The inner layer should be wool, silk, or synthetic fabric that wicks moisture; cotton is a poor choice because it holds moisture. The middle layer is wool, fleece, or synthetic insulation that keeps warmth even when damp. The outer layer is a wind- and rain-resistant shell that still allows some ventilation to prevent overheating and sweat buildup. Insulated waterproof boots, insulated gloves, and a hat or balaclava round out the system, since heat escapes fastest from the head and extremities.
When the Warning Came Too Late: First Aid
Cold stress injuries respond badly to well-meaning improvisation, so getting the response right matters.7Occupational Safety and Health Administration. Cold Stress Guide
For hypothermia, call 911 for moderate to severe cases. Move the person to a warm room or vehicle, replace wet clothing with dry layers, and cover the body, head, and neck with blankets and a vapor barrier such as a tarp, leaving the face uncovered. If medical help is more than 30 minutes away and the person is alert, give warm sweetened drinks; never give liquids to someone unconscious. Place warm bottles or hot packs against the armpits, sides of the chest, and groin. Begin CPR if the person has no pulse and isn’t breathing, and continue until help arrives.
For frostbite, do not rub the affected skin with snow, hands, or anything else. Do not apply direct heat from a stove, heat lamp, or heating pad, and do not break blisters. Cover the area loosely and protect it from further contact. If there’s any chance the tissue could refreeze before reaching medical care, leave rewarming to professionals; a freeze-thaw-refreeze cycle causes far more tissue destruction than the original injury.
Legal Backing and Penalties
The lack of a dedicated cold-weather standard doesn’t limit OSHA’s authority. The agency enforces cold stress protections through the General Duty Clause. If OSHA determines that an employer knew or should have known about a cold stress hazard and failed to address it, a citation can follow.
Penalty amounts are adjusted for inflation each year. As of the adjustment effective January 2025, the maximum fine for a serious violation is $16,550 per violation. Willful or repeated violations carry a maximum of $165,514 per violation. Failure to correct a cited hazard by the abatement deadline costs up to $16,550 per day.8Occupational Safety and Health Administration. OSHA Penalties
Reporting duties apply the same way they do for any serious workplace injury. A work-related fatality must be reported to OSHA within 8 hours. An in-patient hospitalization, amputation, or loss of an eye must be reported within 24 hours.9Occupational Safety and Health Administration. Reporting Fatalities, Hospitalizations, Amputations, and Losses of an Eye Severe frostbite requiring amputation falls under the 24-hour rule. Cold-related injuries are also recordable on the OSHA 300 log when they result in death, days away from work, restricted duty, job transfer, medical treatment beyond first aid, or loss of consciousness.10Occupational Safety and Health Administration. General Recording Criteria