If you live in a city, you likely know that most of these urban areas experience hotter hots than their surrounding rural land. This “heat island” effect can cause a city to be up to 12 degrees F hotter than surrounding areas. But not all cities are created equal in this measure.
A new study, published July 9 in the journal Nature, found that this heat island effect is largely influenced by how much and what kind of vegetation is present in the rural areas, the study said. The types of vegetation is determined by the climate — how much rain and snow the area gets.
A city built in a wet environment, like, say, New Orleans replaces lots of trees. These trees suck up heat out of the ground, keeping the rural areas cooler. When they are absent in cities, the cities have higher heat island effects.
In drier areas there is more low lying brush, which doesn’t wick away heat as well as wet trees. That means that the difference in temperature between the city and a surrounding rural area in a dry climate is smaller.
For example, New Orleans is about 10 degrees F hotter than its surroundings, but in Los Angeles this difference is less than 6 degrees F.
Larger cities also get hotter than their surroundings since there is more time for heat to build up during the day and less time to dissipate during the cooler nights.
Here’s how bad your city is at dealing with heat: “Daytime ΔT” shows how much hotter the city is than the surrounding area in degrees C (1 degree C = 1.8 degrees F). Luckily this heat island effect usually makes for milder winters in the city, too.