Workplace Temperature Rules in Canada — Heat & Cold Stress

Canada works through +30°C summers and −30°C winters, and the law does not leave that to chance. There is no single legal maximum or minimum working temperature, but every jurisdiction makes the employer responsible for protecting workers from heat and cold stress. Several write the thresholds directly into regulation, from Ontario's 18°C indoor minimum to Quebec's mandatory heat-stress limits. This guide covers Canada's workplace temperature regulations in plain terms: what heat and cold stress are, the temperature thresholds and how they're measured, the federal and provincial requirements, and the training employers must provide.

What are occupational heat stress and cold stress?

Heat stress is the total heat load on the body from the work itself, the environment and the clothing worn; heat strain is the body's physiological and behavioural response to that heat. It is driven by more than the reading on a thermometer. Humidity, radiant heat from the sun or from equipment, how hard the work is, and how much the clothing or protective gear traps heat all add to the load 10. As the body loses water and salts through sweating, the strain shows itself as cramps and heavy sweating, weakness, dizziness and nausea. At its most serious, it shows as the confusion and collapse of heatstroke. Symptoms vary according to the type and severity of the heat illness, and serious heat illness can develop rapidly 11.

Cold stress is the opposite problem: the body loses heat faster than it can produce it, and the core temperature starts to fall. Wind and moisture make it worse, because both strip heat from the skin far faster than still, dry air at the same temperature. It shows up first in the extremities and the exposed skin of the face, hands and feet, as numbness, pale or waxy patches, clumsiness and shivering, and in its serious form as hypothermia 12.

Together, heat stress and cold stress are called thermal stress, the term Manitoba's regulation and the new federal provisions use 18,7. Both are easier to prevent than to treat. Workers who know the early signs, and who have water, shade, warm-up areas and the right clothing available, are far less likely to reach the point where the situation becomes an emergency.

Heat stress and cold exposure are examples of physical hazards — workplace agents like noise, vibration and radiation that harm the body through physical conditions rather than chemicals. 13

What are the signs and symptoms of heat stress and cold stress, and what is the first aid?

This guide focuses on six common heat- and cold-related conditions, three from each, running from mild to life-threatening. They are not the only ones: heat syncope and heat rash, and chilblains and immersion foot, also occur in Canadian workplaces 11,12.

What are heat cramps?

Heat cramps are painful muscle spasms, usually in the legs, arms or abdomen, caused by the water and salts lost through heavy sweating. Move the worker to a cool place, have them rest, give water or an electrolyte drink, and stretch the affected muscle gently 14. Do not send them straight back to hard physical work.

What is heat exhaustion?

Heat exhaustion means the body is losing the struggle to cool itself. The signs are heavy sweating, cool and clammy skin, weakness, headache, dizziness, nausea and a fast, weak pulse. Get medical aid. Stay with the worker, move them to a cool or shaded area, remove excess clothing, cool the skin with damp cloths or a fan, and provide water or a sports drink if they are able to drink. Heat exhaustion can progress quickly to heatstroke, so do not leave the worker alone to recover 11.

What is heatstroke?

Heatstroke is a medical emergency. A normal body temperature is approximately 37°C 8, and in heatstroke the body loses the ability to control it: the body temperature is often greater than 40°C 11. The worker may have hot, dry skin or may still be sweating heavily, together with confusion, altered behaviour, slurred speech, seizures or loss of consciousness. Call emergency services immediately. While waiting, move the worker into shade or a cool space, remove excess clothing and cool them aggressively with water, wet cloths or ice packs to the neck, armpits and groin. Do not give fluids to a worker who is not fully conscious 11.

What is frostnip?

Frostnip is the mild form of frostbite, and the warning that tissue damage is coming. The skin looks yellowish or white but is still soft to the touch, and there may be tingling or numbness. Get the worker somewhere warm and rewarm the area gently with body heat or warm, not hot, water. Do not rub the skin 8.

What is frostbite?

Frostbite is the freezing of the skin and the tissue beneath it. The area feels hard and waxy, looks white, grey or blotchy, and loses feeling entirely. Move the worker to a warm area, remove wet or constricting clothing, protect the affected area with a loose sterile dressing, and seek medical attention. Do not rub the area, and do not attempt to thaw it on site if it could refreeze, because refreezing after thawing causes further tissue damage 12.

What is hypothermia?

Hypothermia sets in when the core body temperature falls below 35°C (95°F). Uncontrollable shivering, slurred speech, clumsiness, confusion and drowsiness come first, and in severe cases the shivering stops altogether, which is a sign the body can no longer warm itself. Call for help, move the worker to a warm shelter, replace wet clothing with dry layers, and wrap them in blankets, including the head. Warm sweet drinks help only if the worker is fully conscious, and alcohol never does 12.

Wind matters as much as the temperature reading in cold work, because wind chill describes what the cold actually does to exposed skin. The risk of health effects such as windburn and frostbite rises at wind chill values below −27 8.

What are the main heat and cold safety practices at work?

What are the safety practices for working in the heat?

• Drink water steadily through the shift, before thirst sets in, rather than in large amounts at break time.
• Take rest breaks in a shaded or air-conditioned area, and make them longer and more frequent as the conditions get hotter.
• Wear light, loose-fitting clothing in a breathable fabric.
• Use sun protection where the work is outdoors: a wide-brimmed hat, sunscreen and shade wherever it can be set up. 31

What are the safety practices for working in the cold?

• Dress in layers, with a windproof and waterproof outer layer that can be opened to release sweat.
• Cover the head and protect the hands with gloves or mitts suited to the task.
• Wear insulated, waterproof footwear with a sole that grips.
• Use heated shelters or portable heating so workers can warm up before they get cold, not after. 32

What practices apply to both heat and cold?

• Train workers to recognize the symptoms of heat and cold stress in themselves and in their co-workers.
• Assess the risk before the work begins: the conditions, the workload, the clothing and PPE, and how long the exposure will last.
• Monitor the thermal conditions, which several jurisdictions require by law where the thermal environment may be a hazard, including Saskatchewan, New Brunswick, Newfoundland and Labrador, Yukon, the Northwest Territories and Nunavut 19,20,21,23,28,29.
• Keep communication open, so a worker can report worsening conditions or early symptoms without hesitating.

Does the law require workers to be trained on heat and cold stress?

Heat and cold stress safety training teaches workers how the body responds to extreme temperatures. It teaches them to recognize heat cramps, heat exhaustion, heatstroke, frostnip, frostbite and hypothermia in themselves and in their co-workers, and to control exposure before it turns into an emergency. Training is also one part of meeting the rules that actually apply to a workplace. Manitoba and New Brunswick write instruction in the symptoms and the precautions into regulation 18,19, and Yukon requires instruction in the symptoms of heat disorders 29; the measurements, procedures and controls the same rules require belong to the employer.

Who is responsible for protecting workers from heat and cold stress?

The employer is responsible. Everywhere in Canada the employer must protect workers from heat and cold stress, and in some jurisdictions the training itself is statutory. In Manitoba, for example, the employer must give workers "information, instruction and training" in the symptoms of thermal stress and the precautions to avoid injury 18. New Brunswick requires a competent person to measure and record thermal conditions 19; Newfoundland and Labrador, Saskatchewan and the territories require monitoring instruments where the thermal environment may be a hazard 20,28,21,23. Workers carry their share: follow the training, use the clothing and PPE provided, and report symptoms — in themselves or in a co-worker — early.

Is there a legal maximum or minimum working temperature in Canada?

There is no single legal maximum or minimum working temperature in Canada, but the thresholds are far more concrete than most workers think. Several jurisdictions set indoor minimums, six provinces make the ACGIH exposure limits for heat and cold binding, and two jurisdictions prescribe how heat stress must be measured.

• Indoor minimums exist. Ontario's industrial regulation requires enclosed workplaces to be kept at not less than 18°C (with practical exceptions for freezers, loading doors and the like) 24. New Brunswick, Prince Edward Island and Quebec all set minimums by type of work instead, at roughly 12°C for heavy work and 20°C for light work 19,26,27. Federally, personal service rooms and food preparation areas must sit between 18°C and 29°C where feasible 3.
• Heat limits come from the ACGIH TLVs. The heat-stress Threshold Limit Values are published by the American Conference of Governmental Industrial Hygienists and built around keeping core body temperature below 38°C. They are adopted as law in British Columbia, Manitoba (which names the 2019 edition), New Brunswick (2016 edition, including its work-rest regimen for heat and work-warming regimen for cold), Nova Scotia, Prince Edward Island and Newfoundland and Labrador. Ontario's heat-stress guidance uses them as its reference 9.
• Two jurisdictions prescribe the measurement method. In Quebec, heat stress is measured by the WBGT method under the regulation itself, and when the index crosses the continuous-work curve the employer must provide medical supervision, water at 10–15°C and one shower per 15 exposed workers 27. In Yukon, where hot conditions could cause heat disorders, the thermal index must be determined and recorded using WBGT or WGT. The limits for continuous work fall as the workload rises: roughly 30–32°C for light work, 28–31°C for moderate work and 26–29°C for heavy work, depending on air velocity 29.
• Cold has its own triggers. In British Columbia, the cold rules engage when conditions could drop a worker's core temperature below 36°C or fall past the ACGIH wind-cooling criteria 17. The wind chill index, what the temperature feels like on exposed skin, drives the practical guidance everywhere.
• Humidex is a screening tool. The humidex rating combines temperature and humidity into what the air feels like, and it can be useful in some workplaces, particularly where radiant heat and heavy workloads are not major factors. Where legislation or an applicable standard requires WBGT or another method, that method must be used 10.

What is the federal legislation for heat and cold?

For federally regulated employers, the Canada Labour Code, Part II sets the duty. The Code requires employers to:

• ensure the health and safety at work of every employee (s. 124) 1;
• provide each employee with the "information, instruction, training and supervision necessary to ensure their health and safety at work" (s. 125(1)(q)) 2;
• provide prescribed sanitary and personal facilities: under the COHSR, personal service rooms and food preparation areas must be kept between 18°C and 29°C where feasible (s. 9.9) 3.

Section 9.9 is one relevant federal temperature provision rather than a complete inventory. Others apply to specific situations. Where the heat of motorized materials handling equipment pushes the operator's compartment above 26°C, the compartment must be protected by an insulated barrier (s. 14.9(2)) 4. A first aid room must be kept at 21°C or warmer whenever it is 21°C or colder outside. Where feasible, it must also be no warmer than the outdoor air once that passes 24°C in the shade (s. 16.10(2)(b)) 5.

Beyond those specifics, thermal protection flows through the hazard-prevention program: assess the heat and cold hazards of the work, control them, and train workers on them 6.

Amendments registered on January 30, 2026 (SOR/2026-10) add a dedicated thermal stress section to the COHSR (s. 10.19.3), with effect from January 30, 2027. The employer must develop procedures to reduce the risk of thermal stress: engineering and administrative controls, monitoring of environmental factors, protective clothing and equipment, and employee education and training on the signs and symptoms. Those procedures must be applied whenever conditions reach the ACGIH screening criteria for heat stress or its cold stress thresholds 7.

Everyone else falls under provincial or territorial law, which is set out below.

What are the workplace temperature regulations in each province and territory?

Thermal rules differ sharply by jurisdiction. Some write numbers and named standards into regulation, others rely on the employer's general duty and published guidance. This is what each one requires.

Which workers are most exposed to heat and cold stress?

Workers who may be exposed to hazardous heat or cold should receive heat- and cold-stress information, instruction and training appropriate to their jurisdiction and to the hazards of their own workplace. Examples of industries with significant exposure include the following.

• Construction. Work runs outdoors through both seasons, often in poorly ventilated enclosed spaces, and the protective equipment itself adds to the heat load.
• Agriculture. Long summer days of physically demanding outdoor work, with little shade and peak effort at the hottest part of the season.
• Mining. Underground heat and surface cold, heavy labour and long shifts, frequently far from immediate medical help.
• Forestry. Sustained physical work in remote locations, exposed to whatever the weather does over a full shift.
• Outdoor recreation. Guides and instructors work in changeable conditions, often remotely and over extended hours, and are responsible for other people as well as themselves.

Heat is not an outdoor-only hazard. Kitchens, foundries, bakeries and laundries put workers in proximity to a heat source such as an oven, or in a hot room with inadequate ventilation, and the same thresholds and symptoms apply there 11.

What must workers be taught about heat and cold stress?

Heat and cold stress training gives workers the knowledge to work safely in extreme temperatures. Where a regulation names the content, it names the symptoms of thermal stress and the precautions to take (Manitoba s. 4.12 18, New Brunswick s. 23 19, Yukon s. 12(4) 29). From January 30, 2027, federally regulated employers' thermal stress procedures must also include employee education and training on the signs and symptoms of thermal stress (COHSR s. 10.19.3) 7. A complete course covers:

• How the body handles heat and cold, and what heat cramps, heat exhaustion, heatstroke, frostbite and hypothermia look like, in yourself and in co-workers
• The thresholds and how they're measured: ACGIH limits, WBGT, humidex, wind chill
• Controls, in order: engineering (shade, ventilation, shelters, heating), administrative (work-rest and work-warming schedules, scheduling around peak conditions), and clothing and PPE
• Hydration and warm-up or cool-down practice, including why acclimatization matters for new and returning workers
• Emergency response: recognizing an emergency, such as heatstroke or advanced hypothermia, and first aid until help arrives
• The rules: your jurisdiction's thermal provisions and the duties of employers and workers

In addition to these topics, training has to connect to the workplace it is used in. That means the thermal hazards identified in your own risk assessment, your employer's hot- and cold-weather procedures, and who to notify when conditions change or a co-worker shows symptoms.

Does the law set an expiry date for the training?

No Canadian statute or regulation sets an expiry date for heat and cold stress training, and no standard fixes a renewal cycle for it: the thermal-stress provisions reviewed for this guide do not prescribe any expiry for a certificate. The eSafetyFirst certificate carries a printed expiry of two years from completion; that is the program's practice, not a legal requirement. Refresher training is common practice, set by employers' training policies and their clients' requirements.

Refresher instruction may be needed sooner when hazards, duties or procedures change. A new site or role with different thermal conditions, an incident or close call, or a season's first stretch of extreme weather are all reasons to re-brief before any printed date comes up.

Key takeaways

Canada's temperature rules are real and specific: minimums indoors, ACGIH limits written into law, and WBGT measurement in Quebec and Yukon. The employer owns the duty and, in several jurisdictions, the monitoring that goes with it. Training is how workers come to recognize the danger before it becomes an emergency.