Local Climate

According to a recent Atlantic article, "New England is warming more quickly than almost anywhere else on Earth." What are we doing to cope?

Shade Makes A Difference

Shade trees make a tremendous contribution to quality of life in our public spaces, especially in summer. Just look below at the temperature readings taken around town on a (very) hot summer day.

Shaded Trail

Lincoln Field

Lexington High School

Public Spaces

Many of our public spaces have little shade and are brutally hot in the summer. Try to enjoy a picnic on the Battle Green in July. There's a reason you won't see many people doing the same.

Places like Harvard Yard are well shaded and comfortable in the summer heat.

Battle Green


Hastings


Harvard Yard


Playgrounds

We want our kids to play outside in the summertime!

But that's not so easy in Lexington. Scroll through to compare our playgrounds with shaded ones in Cambridge.

Mean Radiant Temperature: How It Feels

Air temperature alone is not sufficient to determine how comfortable you will feel outside. That is because the air is not the only source of heat you are exposed to, or even the dominant heat source. The sun's radiation is an obvious contribution, but less obvious is the thermal radiation from the ground or other surfaces. While you can't see this infrared radiation, it is an important factor, as anyone walking across a hot parking lot can attest. When you combine all these factors, you come up with something called the mean radiant temperature.

Various studies have shown that tree cover has a very significant impact on mean radiant temperature. For example:

  1. The influence of increasing tree cover on mean radiant temperature across a mixed development suburb in Adelaide, Australia (link)

    • "Directly below clusters of trees, Tmrt could be reduced by between 14.1 °C and 18.7 °C"

  2. Modelling the impact of increased street tree cover on mean radiant temperature across Vancouver’s local climate zones (link)

    • "Modelling suggested that a pedestrian standing directly under a tree canopy would experience Tmrt reductions of 15.5–17.3 °C"

  3. The Comparison of the Solar Radiation and the Mean Radiant Temperature (MRT) under the Shade of Landscaping Trees in Summertime (link)

    • "Therefore, it can be said that the tree canopies can reduce the MRT around 10-16°C"