When Is It Too Cold to Work? How to Prevent Hypothermia

The weather now is more unpredictable than ever. Record-breaking cold spells now alternate with record-breaking heat waves in many places. Cold work stresses the body in many ways and may lead to hypothermia. Everyone has a different tolerance to cold stress. Please don’t get sick from the cold by knowing when it is too cold to work.  

Can Being Cold Make You Sick?

You cannot catch a cold from cold air. Still, irritation from cold air can cause bronchospasms and asthma incidents in susceptible people, and immune function may be impaired, leading to an increased chance of a respiratory infection. Cold work is related to chronic muscle and joint problems such as back pain, knee problems and carpal tunnel.

Studies show an increased rate of hospitalizations for coronary heart disease (CHD) and stroke when the weather is cold. If you have risk factors for these conditions, use extra precautions when the weather turns bad. Cold temperatures can also affect reasoning, vigilance, and the risk of unsafe behaviour, which can impair work performance and increase the risk of accidents.

When the skin’s surface is frozen, it is called frostbite or frostnip. The longer the skin is frozen, the deeper the freezing goes, and the more dangerous your situation.  Death of the tissue may occur, and permanent damage may result. In extreme cases, the extremity will have to be amputated. 

What Happens When You Are Out In The Cold?

Your body must maintain a relatively constant temperature (around 37 Celsius (98.6 °F). If your body temperature gets too low, your bodily systems cannot work correctly, which can lead to complete failure and death.

Physical activity increases heat generation inside the body and protects against getting cold. Cold air temperatures, being wet or emersed in water, and windy conditions increase your body’s heat loss. Wind displaces the warm layer of air around your body and evaporates moisture on your skin. The wind can make you feel cold even in relatively warm temperatures.  This is known as wind chill.

When your body is cold, it shuts down the blood circulation close to the skin and the extremities, such as the hands and feet. Your body conserves heat but keeps the blood flowing to your core and vital organs. Painful or numb hands, feet and exposed surfaces on the face are one of the first signs of trouble, and you should seek a more hospitable environment. Manual dexterity and motor coordination quickly decrease in the cold, making it very difficult to do relatively simple tasks, which can impair work performance and increase the risk of accidents.


When your body temperature gets below 35 °C (95 °F), you have hypothermia and are in severe danger. The brain is one of the first organs to be affected, and hypothermic persons are often unaware of their dangerous situation.   

The warning signs of hypothermia include.

  • Shivering
  • Slurred speech or mumbling
  • Slow, shallow breathing
  • Weak pulse
  • Clumsiness or lack of coordination
  • Drowsiness or fatigue
  • Confusion or memory loss
  • Loss of consciousness

Falling into the water near the freezing point will quickly make you hypothermic. A person is likely to survive only 15 to 45 minutes.

When Is It Too Cold to Work?

The United States, Europe and Canada all have the requirement that the employer takes reasonable precautions for the safety of the worker. All workers across Canada, the United States and Europe have the right to refuse unsafe work. If you notice any warning signs listed above, such as shivering, slurred speech or mumbling, let your boss know and warm up in a heated area. Cold stress can quickly escalate to hypothermia, putting your life in danger.

There is no specific minimum temperature that applies to all workplaces. The minimum temperature you can be asked to work in will depend on the particular conditions of the work environment and the nature of your work. Most legal jurisdictions in North America have a suggested minimum of 18 °C for indoor work but allow many exceptions, such as where the workplace is normally unheated, or the necessity of opening doors makes the heating of the area impracticable. Many jurisdictions reference the current ACGIH TLVs® for heat and cold exposure. Unfortunately, the cold stress guidelines are unavailable to the general public. 

Wind Chill

Fortunately, Canada’s internationally accepted wind chill index provides an excellent way to evaluate the harmful effects of cold. The wind chill index is displayed in temperature-like units. By equating the outdoor conditions to an equivalent temperature with no wind, the index represents the degree of “chill” that your skin senses. Check the wind chill on your local weather television forecast or mobile phone application before you go to work or on a hike.

Wind Chill Temperature and Risk

0 to -9 Low risk
-10 to -27Moderate risk
-28 to -39High risk: exposed skin can freeze in 10 to 30 minutes
-40 to -47Very high risk: exposed skin can freeze in 5 to 10 minutes
-48 to -54Severe risk: exposed skin can freeze in 2 to 5 minutes
-55 and colderExtreme risk: exposed skin can freeze in less than 2 minutes

The weather now is more unpredictable than ever. Always check the windchill and temperature when working outside. Dress appropriately and warm up frequently. You have the right to a safe work environment. Let your boss know when it is too cold to work. You may also work in the heat if you work in the cold.  Check out “When Is It Too Hot To Work” And the Free Heat Stoke and Heat Exhaustion Prevention Training.

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