What Are Heat Islands and Why Should You Care?

Heat Island Map of Cambridge

What Are Heat Islands and Why Should You Care?

City heat is a special kind of heat. Ask anyone living in an urban area in the month of August. We’re familiar with the fact that cities can be warmer than rural areas—the difference can be as much as 20 degrees Fahrenheit! City buildings also amplify and pump out excess heat and a lack of shade can increase the heat even more.


Even within urban areas, there are spots that are hotter still—where heat becomes super concentrated. These hot spots are known as heat islands. In a heat island, the temperature is significantly warmer than the areas around it. Heat islands can be caused by dark paved surfaces and roofing as well as tree-less landscaping. The heat that buildings themselves create through air conditioning and energy use can also contribute to a heat island effect.

Heat islands are not just about comfort—they also cause and exacerbate  public health risks, from heat stress to increased levels of ozone and air pollution, which can easily reach dangerous levels for children, seniors and anyone with compromised health. Extreme heat, in fact, kills more people in the US annually than any other type of environmental disaster.

The map above shows the location of Cambridge’s own hot spots. The areas in red experience the most intense heat. If you are familiar with Cambridge, you can see that some wealthier and whiter neighborhoods tend to have less of that heat, while some lower-income and BIPOC neighborhoods tend to have more.


Cambridge is currently piloting several programs to reduce the impact of heat islands, especially in its BIPOC communities. Property owners can help by choosing thoughtful shade-giving landscaping, energy-saving materials and appliances, green building materials that do not contribute to air pollution, roofing that reflects heat back into the atmosphere rather than absorbing it, and paving made from permeable materials.

You can contribute to climate research and resilience planning Projects like these require detailed maps filled with data about temperature and that’s where citizens can make a difference.

You can contribute to that project and make the data even richer. Sign up at ISee to contribute to heat island data sets and become a citizen scientist!

Finally, check out the city’s Sustainability Dashboard to see how Cambridge is doing. If you think Cambridge can and should be doing better, speak up. Get involved.

If you have ideas and suggestions, please share them! Responding to increasing heat and the climate crisis is going to take every good idea we can find.

Lend your helping hands and make our city cool again.

Join us to explore heat islands and how Cambridge is responding at our Earth Day Event.

Fri, April 22, 2022
2:00 PM – 4:00 PM EDT


Throwing Shade on Cambridge's Heat Islands

Explore the Cloud House, learn about climate change and design your own cloud house model. Free for all!
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