Public Health

Since it affects the social and environmental determinants of health including - clean air, clean water, food insecurity and housing security - climate change can have direct and indirect effects on health.

Case Studies

Explore case studies to learn about how data was used to impact climate related decisions in specific contexts.

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Variables related to Public Health

Explore variables to learn about how data was used to impact climate related decisions in specific contexts.

The Hottest Day describes the warmest daytime temperature in the selected time period. In general, the hottest day of the year occurs during the summer months.

High temperatures are important. They determine if plants and animals can thrive, they limit or enable outdoor activities, define how we design our buildings and vehicles, and shape our transportation and energy use. However, when temperatures are very hot, people – especially the elderly – are much more likely to suffer from heat exhaustion and heat stroke. Many outdoor activities become dangerous or impossible in very high temperatures.

Technical Description:

The highest maximum temperature (Tmax) in the selected time period. Use the Variable menu option to view annual, monthly or seasonal values for this index.

 


Mean temperature describes the average temperature for the 24-hour day.

The average temperature is an environmental indicator with many applications in agriculture, engineering, health, energy management, recreation, and more.

Technical description:

The average of the daily maximum temperature (Tmax) and the daily minimum temperature (Tmin). Use the Variable menu option to view annual, monthly or seasonal values for this variable.


Minimum temperature describes the coldest temperature of the 24-hour day. Typically, but not always, the minimum temperature occurs at night and so this variable is commonly referred to as the nighttime low.

The average lowest temperature is an environmental indicator with many applications in agriculture, engineering, health, energy management, recreation, and more.

Technical description:

The daily minimum temperature (Tmin). Use the Variable menu option to view annual, monthly or seasonal values for this variable.


Days with Tmax > 25°C describes the number of days where the daytime high temperature is warmer than 25°C. This index gives an indication of number of summer days in the selected time period.

High temperatures are important. They determine if plants and animals can thrive, they limit or enable outdoor activities, define how we design our buildings and vehicles, and shape our transportation and energy use. However, when temperatures are very hot, people – especially the elderly – are much more likely to suffer from heat exhaustion and heat stroke. Many outdoor activities become dangerous or impossible in very high temperatures.

Technical description:

The number of days with a maximum temperature (Tmax) greater than 25°C. Use the Variable menu option to view annual, monthly or seasonal values for this index.


Days with Tmax > 27°C describes the number of days where the daytime high temperature is warmer than 27°C.

High temperatures are important. They determine if plants and animals can thrive, they limit or enable outdoor activities, define how we design our buildings and vehicles, and shape our transportation and energy use. However, when temperatures are very hot, people – especially the elderly – are much more likely to suffer from heat exhaustion and heat stroke. Many outdoor activities become dangerous or impossible in very high temperatures.

Technical description:

The number of days with a maximum temperature (Tmax) greater than 27°C. Use the Variable menu option to view annual, monthly or seasonal values for this index.


Days with Tmax > 29°C describes the number of days where the daytime high temperature is warmer than 29°C.

High temperatures are important. They determine if plants and animals can thrive, they limit or enable outdoor activities, define how we design our buildings and vehicles, and shape our transportation and energy use. However, when temperatures are very hot, people – especially the elderly – are much more likely to suffer from heat exhaustion and heat stroke. Many outdoor activities become dangerous or impossible in very high temperatures.

Technical description:

The number of days with a maximum temperature (Tmax) greater than 29°C. Use the Variable menu option to view annual, monthly or seasonal values for this index.


Days with Tmax > 30°C describes the number of days where the daytime high temperature is warmer than 30°C. This index gives an indication of number of hot days in the selected time period.

High temperatures are important. They determine if plants and animals can thrive, they limit or enable outdoor activities, define how we design our buildings and vehicles, and shape our transportation and energy use. However, when temperatures are very hot, people – especially the elderly – are much more likely to suffer from heat exhaustion and heat stroke. Many outdoor activities become dangerous or impossible in very high temperatures.

Technical description:

The number of days with a maximum temperature (Tmax) greater than 30°C. Use the Variable menu option to view annual, monthly or seasonal values for this index.


Days with Tmax > 32°C describes the number of days where the daytime high temperature is warmer than 32°C. This index gives an indication of number of very hot days in the selected time period.

High temperatures are important. They determine if plants and animals can thrive, they limit or enable outdoor activities, define how we design our buildings and vehicles, and shape our transportation and energy use. However, when temperatures are very hot, people – especially the elderly – are much more likely to suffer from heat exhaustion and heat stroke. Many outdoor activities become dangerous or impossible in very high temperatures.

Technical description:

The number of days with a maximum temperature (Tmax) greater than 32°C. Use the Variable menu option to view annual, monthly or seasonal values for this index.


Tropical Nights (Days with Tmin >18°C) describes the number of days where the nighttime low temperature is warmer than 18°C. 

Hot summer days and heat waves become particularly stressful if overnight temperatures do not provide cooling relief. Tropical nights make it more difficult for the body to cool down and recover from hot days.

Elderly people, the homeless, and those who live in houses or apartments without air conditioning are especially vulnerable during these heat events, particularly if they last for more than a few days.

Technical description:

A Tropical Night occurs when the daily minimum temperature (Tmin) is greater than 18°C. Use the Variable menu option to view the annual, monthly or seasonal values for this index. Visit the Analyze page to calculate Tropical Nights using different minimum temperature thresholds.


Tropical Nights (Days with Tmin >20°C) describes the number of days where the nighttime low temperature is warmer than 20°C. 

Hot summer days and heat waves become particularly stressful if overnight temperatures do not provide cooling relief. Tropical nights make it more difficult for the body to cool down and recover from hot days.

Elderly people, the homeless, and those who live in houses or apartments without air conditioning are especially vulnerable during these heat events, particularly if they last for more than a few days.

Technical description:

A Tropical Night occurs when the daily minimum temperature (Tmin) is greater than 20°C. Use the Variable menu option to view the annual, monthly or seasonal values for this index. Visit the Analyze page to calculate Tropical Nights using different minimum temperature thresholds.


Tropical Nights (Days with Tmin >22°C) describes the number of days where the nighttime low temperature is warmer than 22°C.  Hot summer days and heat waves become particularly stressful if overnight temperatures do not provide cooling relief. Tropical nights make it more difficult for the body to cool down and recover from hot days.

Elderly people, the homeless, and those who live in houses or apartments without air conditioning are especially vulnerable during these heat events, particularly if they last for more than a few days.

Technical description:

A Tropical Night occurs when the daily minimum temperature (Tmin) is greater than 22°C. Use the Variable menu option to view the annual, monthly or seasonal values for this index. Visit the Analyze page to calculate Tropical Nights using different minimum temperature thresholds.


Growing degree days (GDD) are a measure of whether climate conditions are warm enough to support plant and insect growth. When the daily average temperature is warmer than the threshold temperature, growing degree days are accumulated (see Degree Days Above). For crops such as corn and beans, a threshold temperature of 10°C is generally used.

Technical description:

The number of degree days accumulated above a threshold temperature of 10°C in the selected time period. Use the Variable menu option to view the annual, monthly or seasonal values for this index. Visit the Analyze page to calculate degree days using different threshold temperatures.


Growing degree days (GDD) are a measure of whether climate conditions are warm enough to support plant and insect growth. When the daily average temperature is warmer than the threshold temperature, growing degree days are accumulated (see Degree Days Above). For forage crops and canola, a threshold temperature of 5°C is generally used.

Technical description:

The number of degree days accumulated above a threshold temperature of 5°C in the selected time period. Use the Variable menu option to view the annual, monthly or seasonal values for this index. Visit the Analyze page to calculate degree days using different threshold temperatures.


Cumulative degree days above 0°C can be used to determine when climate conditions are warm enough to support the growth of certain plants and pests. When the daily average temperature is warmer than 0°C, degree days are accumulated (see Degree Days Above).

This index can be used to determine the range of some insects and other pests. For example, the black-legged tick, which carries Lyme disease, requires the accumulation of at least 2800 degree days above 0°C for its survival. Warmer conditions can speed the development rate of these species and lead to an extension of their geographical range.

Technical description:

The number of degree days accumulated above 0°C in the selected time period. Use the Variable menu option to view the annual, monthly or seasonal values for this index. Visit the Analyze page to calculate degree days using different threshold temperatures.