Smart landscape choices can help dial down the temperature, one yard at a time.
Temperatures in San Antonio aren’t just hot this week — they’re scorching. Sidewalks radiate heat after dark, and dappled shady patches and parking spaces under trees feel like precious real estate.
Welcome to the urban heat island effect, San Antonio-style.
The urban heat island is what happens when natural land cover — like grasslands, trees and soil — is replaced with concrete, asphalt and rooftops. All that hard stuff absorbs and re-emits the sun’s heat much more than a patch of prairie or even your backyard. The result? Temperatures in town can be 5 to 10 degrees hotter.
Not only do buildings increase the temperature, but our day-to-day actions (fuel being burned from driving a car, A/C units, gases expelled from buildings, etc.) can constrict air flows. Certain areas in San Antonio feel hotter than others, and in a city growing this fast, it adds up.
For people, urban heat islands mean more than just sweaty commutes. They’re a health issue, especially for vulnerable folks without AC or those working outdoors. They also spike energy use as we crank up the cooling.
So, what about our landscapes? Native and well-adapted trees and plants are tough, and they can help lower the temperature on the ground, but they’re not invincible. Higher nighttime temperatures can stress them out and disrupt their blooming cycles. And shallow-rooted turfgrasses in full sun, without the benefit of shade, can almost be as hot as concrete.
Hotter temperatures can speed up evaporation, meaning precious moisture is lost before plants can even use it.
What can we do? Think green.
- Plant more shade trees.
- Replace hardscapes with permeable materials.
- Choose native and drought-tough plants and trees that don’t need pampering.
And mulch like your garden depends on it — because it does. Every shaded sidewalk and watered-by-rain garden helps cool down our environment.
