Heat Advisories and Response

Heat and Your Health

Humidity and temperature affect the body's ability to cope with heat.

Everyone can be affected by heat. Individuals at increased risk for heat illness include: 

  • people with chronic health conditions,
  • older adults,
  • people living alone,
  • people on certain medications,
  • people performing strenuous activity in the heat,
  • homeless people,
  • infants and young children.

Early in the summer, hot temperatures may have a greater impact on health because people have not had a chance to acclimatize (adapt) to the heat. Heat may have a greater impact on people living in the north because of the acclimatization (adaption) to cooler temperatures. In addition, there may be fewer ways to get relief from the heat (e.g. fewer buildings with air conditioning).

There can be smaller areas that experience higher temperatures than other parts of a region. For example, downtown Winnipeg is usually hotter than other parts of the city and locations outside of the city.

Be aware of how you are coping with the heat. Symptoms of heat illness can include:

  • headache,
  • nausea,
  • dizziness,
  • weakness or tiredness,
  • confusion,
  • rapid breathing and
  • rapid pulse. 

If you experience these symptoms or otherwise feel unwell, move to a cool or shaded place immediately, lie down, sip water and sponge your skin with cool water. Emergency medical attention may be required depending on the severity and duration of symptoms.

For more information on heat, visit our page Heat and Your Health or contact Health Links-Info Santé at 204-788-8200 or 1-888-315-9257.

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Changes to Heat Warnings in Manitoba
  • In June of 2017, Environment and Climate Change Canada (ECCC) in conjunction with Health Canada, and Manitoba Health, Seniors, and Active Living, implemented a new Heat Warning Service for all of Manitoba.
  • The new heat warnings are based on criteria developed during a multi-year collaboration of federal partners and a variety of health stakeholders.
  • The service aims to help reduce heat health risks and ensure consistency of warnings.
  • Health Canada and Environment and Climate Change Canada developed the health-related criteria for new Manitoba heat warnings based on the relationship between health effects and climate. Environment and Climate Change Canada (ECCC) adopted the new criteria as the basis of its Heat Warning criteria which will differ across the province with two region-specific protocols (north and south).
  • The new Northern/Southern criterion is based on health evidence and climatology for each region.
  • To determine when the warning should be issued, forecasters will assess the certainty of experiencing two consecutive days of weather that meets or exceeds the criteria set for humidex and temperature (daytime highs and nighttime lows). If either humidex or temperature conditions are expected to be met for two or more days, a Heat Warning will be issued. ECCC previously issued warnings if old heat criteria were met for one day.
  • As a result of the new service, Manitobans may see changes in the number of Heat Warnings being issued for some regions. The changes are due to the new criteria requiring two days of meeting expected criteria, as opposed to the old criteria of just one day. Further, there are new temperature and humidity thresholds which vary among the two regions. The old criteria were based on one day humidex of equal or greater than 40°C and dewpoint temperature equal or greater than 15°C for the whole province.

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New Heat Warning and Extended Heat Warning Criteria


(daytime high)

(night-time low)


Northern Manitoba




Southern Manitoba








2 days of the above conditions






3+ days of the above conditions



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Heat Advisories
  • Manitoba Health may issue a heat advisory when most Manitobans should consider modifying their activities to prevent health effects related to the heat. Advisories may be issued when it is the first hot weather of the season, there is a special event occurring in the province with a mass gathering of people, or Environment and Climate Change Canada issues an Extended Heat Warning.

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The Heat Alert Response System (HARS)
  • To lessen the potential health impacts of heat on residents, Manitoba Health has worked with partners such as the Regional Health Authorities, social services and emergency response sectors to create a Heat Alert Response System (HARS).
  • The HARS is a two-tiered system of warnings (Heat Warnings and an Extended Heat Warnings) based on the level of heat and the anticipated length of the heat event. Manitoba Health notifies partners of the level of extreme heat forecasted so that appropriate preparations and responses can be put into place.
  • The HARS continues to develop with more partners becoming involved. The transition from one level of warning to another depends on a number of factors, including the duration of the heat event, the humidity and temperature, and overnight temperatures. The response system is evaluated each year. Partner organizations may implement measures to assist people in coping with heat, such as extending public pool hours, handing out water and opening cooling stations.

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Public Health | Environmental Health
Manitoba Health

4th Floor - 300 Carlton St.
Winnipeg MB  R3B 3M9
Phone: 204-788-6735
Fax: 204-948-2040