Cold Stress at Work in Canada: What the Guidelines Actually Say (2026)

Cold stress at work is driven by three factors together: air temperature, wind speed and wetness. Widely used occupational guidance suggests a work-warming regimen once the wind chill temperature reaches or falls below -7°C for continuous outdoor work, with heated warming shelters available nearby. More than 80 people in Canada die each year from over-exposure to cold.

Two things about that guidance surprise most crews. The wind chill figure on a weather app is not the number occupational guidance is built around. And shivering is not a reliable warning sign, because in severe cases it stops. This guide covers what the Canadian guidance actually says, the clothing mistake that makes cold injuries more likely rather than less, and how to build a realistic winter plan before the season starts.

Three stressors, not one temperature

Temperature alone is a poor predictor of risk. CCOHS guidance on cold environments identifies air temperature, air movement and humidity as the factors workers need to be insulated against, and wetness is the one most often underestimated.

Wind strips away the thin boundary layer of warm air the body maintains close to the skin, which is why a mild day with strong wind can be more dangerous than a colder still one. Moisture does something similar from the inside out: wet clothing loses insulating value dramatically, whether the water came from rain, snow or the worker's own sweat.

Cold stress also develops faster where other factors stack up. Low caloric intake, dehydration, fatigue and certain medical conditions all accelerate it, which means the same conditions affect two workers on the same crew very differently.

The wind chill number most crews use is the wrong one

This is worth knowing before you build a policy around a weather app.

Environment and Climate Change Canada publishes a wind chill temperature index, and CCOHS notes explicitly that ECCC recommendations consider all individuals who may be outside, including young children and the elderly. Those recommendations are helpful, but they may not match exposure values or precautions developed by organizations making recommendations specifically for working adults assumed to be in good general health.

In other words, the public advisory and the occupational guidance are calibrated for different populations and different exposure patterns. A crew using the public number is not necessarily being over-cautious or under-cautious, but they are using a figure built for a different purpose.

Occupational guidance developed by the American Conference of Governmental Industrial Hygienists is the reference point CCOHS points to for workers. It suggests a work-warming regimen when work is done continuously in the cold at a wind chill temperature at or below -7°C, with heated warming shelters such as tents, cabins or restrooms available nearby.

CCOHS control measures guidance adds a practical note: where recommendations differ between organizations, and where your jurisdiction sets no established limit, employers are encouraged to choose the system that best protects their workforce. Most Canadian jurisdictions do not set a maximum or minimum outdoor working temperature, so this is a decision employers make rather than one the law makes for them.

The clothing mistake that increases risk

Overdressing is a genuine hazard, and it runs against instinct.

CCOHS is direct about the mechanism: if the work pace is too fast, or if clothing is not properly selected, excessive sweating occurs and the clothing next to the body becomes wet. That moisture dramatically drops the insulation value of the clothing and increases the risk of cold injuries.

The worker who bundles up in a single heavy layer and then works hard is in a worse position by mid-shift than one who layered properly and vented as they warmed. Wet base layers cannot be fixed by adding more on top.

The recommended approach is layers that can be adjusted as work intensity changes, with an outer layer that is wind-resistant in windy weather or waterproof in wet weather. Cover as much exposed skin as possible: a hat, mittens or insulated gloves, a scarf, neck tube or face mask, and insulated waterproof footwear.

Mittens outperform gloves for warmth because fingers share heat, and a two-in-one design keeps dexterity available when needed. Thinsulate flip mitts cover both, and insulated PVC gloves suit wet or chemical-handling work. A knit toque under a hard hat covers the head, and a quilted fleece-lined hooded shirt works as an adjustable mid-layer.

Feet are a separate problem

Immersion foot and trench foot result from having wet feet for a prolonged period, and can lead to gangrene or other infections. They are non-freezing injuries, which means they occur at temperatures well above freezing and catch workers who assume cold injury requires deep cold.

The practical defense is keeping feet dry rather than only keeping them warm. That means genuinely waterproof footwear, changing socks partway through a wet shift, and wool or wool-blend socks that retain some insulating value when damp. Wool work socks are the baseline, and neoprene insulating socks add a layer inside rubber boots.

Boot insulation should match the actual exposure rather than the coldest day imaginable, since an over-insulated boot causes the sweating problem described above. For sustained deep cold, the Muck Arctic Pro CSA boots rated to -50°C are built for it. For general winter work, the STC Blacksmith insulated waterproof boot and the Dunlop Purofort Explorer with Vibram Fire and Ice sole cover wet and icy ground. Our guide to winter work boots works through the selection in detail.

Recognising cold injury, including when shivering stops

Hypothermia progresses in a recognizable pattern. A feeling of cold is followed by pain in exposed body parts, then muscular weakness and drowsiness. CCOHS describes the presentation memorably as stumbles, mumbles and fumbles.

Warning signs include complaints of nausea, fatigue, dizziness, irritability or euphoria, pain in the hands, feet or ears, and severe shivering. Euphoria and irritability are the two most likely to be misread as personality or attitude rather than as symptoms.

Here is the detail that matters most. CCOHS training requirements specify recognising the signs and symptoms of hypothermia or excessive cooling of the body including when shivering does not occur. Shivering can stop as hypothermia becomes severe, so a worker who has stopped shivering is not necessarily improving. Treating shivering as the primary trigger for action means missing the most serious cases.

Freezing injuries run from windburn through frostnip to frostbite, typically affecting fingertips, toes, nose, ears, cheeks and chin. Frostbitten skin can appear white and waxy and feel numb. If frostbite is suspected, get the worker to a warm area, remove wet clothing, loosen anything constricting, and warm them slowly while covering head and neck. Do not rub the affected area, and seek medical help.

The buddy system exists because people are not likely to notice their own symptoms. Confusion and euphoria specifically impair a worker's ability to self-assess, which is why co-worker observation is a control rather than a courtesy.

Building a plan before the season starts

Cold-weather planning done in November is late. The equipment lead times, the training refreshers and the shelter arrangements all take longer than the first cold snap allows.

Elements worth having in place: a work and warm-up schedule tied to wind chill, heated shelters positioned where crews can actually reach them, scheduling that moves outdoor work to warmer parts of the day where possible, and adjusted expectations for pace and lifting, since CCOHS notes work performance and weights lifted should account for the weight and bulkiness of cold-weather clothing.

Avoid assigning prolonged sitting or standing tasks in the cold, since inactivity accelerates heat loss. Encourage frequent warm, non-alcoholic and low-caffeine drinks, and regular eating to maintain body heat.

Training is the piece most often skipped. Workers and supervisors need instruction in safe work practices, re-warming procedures, proper clothing practices, eating and drinking habits, and recognition of cold stress, frostbite and hypothermia. Build a no-heroics culture where calling time on lost dexterity is expected rather than tolerated.

The hazards winter adds to everything else

Cold does not arrive alone. Shorter daylight means crews are working in low light for a larger share of the shift, which raises the stakes on conspicuity. Our guide to high visibility workwear covers what that requires.

Ice changes the traction problem entirely, and an outsole that grips wet concrete may do very little on packed snow. See our guide to slip resistance at work and the complete guide to CSA work boots in Canada.

Bulky gloves reduce grip and dexterity, which is a hazard around tools and machinery rather than merely an inconvenience, as covered in our guide to work gloves for construction workers. A toque under a hard hat must not compromise the suspension, covered in our hard hat safety guide.

For the wider kit and site obligations, see the complete PPE checklist for Canadian workers and our guide to PPE requirements for Canadian construction sites.

Frequently Asked Questions

At what temperature should outdoor work stop in Canada?

Most Canadian jurisdictions do not set a maximum or minimum outdoor working temperature. Occupational guidance referenced by CCOHS suggests a work-warming regimen for continuous outdoor work once wind chill reaches or falls below -7°C, with heated shelters available nearby. Where no local limit exists, employers are encouraged to adopt the system that best protects their workforce.

Is the wind chill on a weather app the right number for work planning?

Not necessarily. CCOHS notes that Environment and Climate Change Canada's recommendations consider all individuals who may be outside, including young children and the elderly, and may not match exposure values developed specifically for working adults in good general health. Use occupational guidance for occupational decisions.

Can hypothermia occur without shivering?

Yes. CCOHS training requirements explicitly include recognising hypothermia or excessive cooling of the body including when shivering does not occur. Shivering can cease as hypothermia becomes severe, so its absence is not a sign the worker is improving. Other warning signs include nausea, fatigue, dizziness, irritability, euphoria and confusion.

Why is sweating dangerous in cold work?

If the work pace is too fast or clothing is poorly selected, excessive sweating makes the clothing next to the body wet. That moisture dramatically reduces the insulation value of the clothing and increases the risk of cold injury. Layering that can be adjusted as work intensity changes is more effective than a single heavy layer.

What are trench foot and immersion foot?

They are non-freezing cold injuries caused by having wet feet for a prolonged period, and can result in gangrene or other infections. Because they do not require freezing temperatures, they catch workers who assume cold injury only happens in deep cold. Keeping feet dry matters as much as keeping them warm.

What should you not do if a worker has frostbite?

Do not rub or massage the affected area. Move the worker to a warm area, remove wet clothing, gently loosen anything constricting, and warm them slowly while covering the head and neck. Avoid direct heat. Seek medical help promptly, and ensure the area will stay warm before rewarming begins.

This guide is general workplace safety information, not medical or legal advice. Suspected hypothermia or frostbite requires prompt medical attention. Cold-work obligations are set by provincial and territorial regulation; confirm yours with the occupational health and safety authority in your jurisdiction, and ensure workers receive proper first aid training.