Interactive Story Map · Austin, Texas
On a summer afternoon, the ground in some Austin neighborhoods runs nearly 10°F hotter than in others just minutes away. I mapped where the city's surface runs hottest, why, who lives there, and what can be done.
All temperatures here are land surface temperature from satellite thermal imagery: the heat of roofs, roads, and ground, which on a summer afternoon runs far hotter than the air. That surface heat drives the urban heat island.
Each neighborhood here is shaded by its average land surface temperature across three recent summers (2022–2024), which I measured from Landsat thermal imagery. Cooler blues, hotter reds.
I chose these six to span the city (east and central, north and south, hills and flats), but the patterns below were measured across all 65 of Austin's neighborhood planning areas. Click any neighborhood to see its numbers.
When trees and soil are replaced with rooftops, roads, and parking, the ground absorbs and stores more heat. Dark, dense surfaces soak up the sun all day and radiate it back late into the night. The result is a measurable temperature gap between the built city and the countryside around it: the urban heat island.
The City of Austin projects that urbanization alone, even before climate change, could raise the city's temperatures by as much as 7°F by 2050.
"Urbanization alone, without projected climate change, could drive urban temperatures up by 7°F by 2050." — City of Austin, Freezing the Urban Heat Island Effect
The hottest neighborhoods cluster in the urban core and east side, in areas that are dense, paved, and historically industrial. The coolest sit in the leafier, hillier areas. Across these six, the gap between hottest and coolest ground is nearly 10°F of surface temperature.
Switch the map to tree-canopy cover and the pattern nearly inverts. Across all 65 neighborhoods, more canopy means lower surface heat, and the relationship is strong and consistent. Trees cool in two ways: they shade surfaces before the sun can load them with heat, and they release water vapor that cools the air directly.
The same pattern holds beyond Austin. A 2025 global study of thermal and ground-station data found canopy's cooling effect is large and dose-dependent.
A 10% increase in tree canopy lowers local air temperature by about 0.8°C; a 30% increase by as much as 1.5°C. — npj Urban Sustainability (2025)
Impervious surfaces (roofs, roads, parking lots) are the other half of the pattern. They absorb solar energy and re-radiate it for hours. The most paved neighborhoods are the hottest, and the relationship is nearly as strong as canopy's, in the opposite direction.
Canopy and pavement move together: neighborhoods with more of one tend to have less of the other. Together they describe most of the variation in where Austin's surface runs hot.
Heat in Austin is shaped first by the physical landscape. Income plays a real but weaker role: lower-income neighborhoods tend to run hotter, though the relationship is moderate and has clear exceptions.
Central East Austin is among the hottest in the city despite rising incomes from gentrification, while leafy, affluent Zilker stays cooler. Part of the pattern is historical: in Austin, as in many US cities, decades of segregation and disinvestment left lower-income and minority neighborhoods with far less tree canopy.
Affluent Westlake (median income $238k) sits under 69% tree canopy; the St. Johns neighborhood ($41k) under just 21%. — Axios Austin, citing the City's State of Our Environment report (2024)
The heat map reflects decades of land-use decisions: where roads were laid, where trees were kept or cleared, which neighborhoods were invested in and which were not.
Central Texas is projected to warm by roughly 3 to 7°F over the next 50 to 100 years, and that regional warming adds to the urban heat island. The hottest, least-shaded neighborhoods today will have the least buffer against it.
"Climate change projections show Central Texas' climate gradually becoming hotter, with temperatures rising three to seven degrees over the next 50 to 100 years." — City of Austin
Because heat tracks canopy and pavement so closely, the most effective interventions are physical and local: planting and protecting trees, and breaking up heat-storing pavement.
Targeting matters. Cooling does the most good where it is hottest and least shaded today, which, given the history, means directing canopy investment into lower-income, low-canopy neighborhoods rather than spreading it evenly. Cool-pavement coatings, reflective roofs, and shaded transit stops add further relief in the most built-up cores.
With all 65 neighborhoods ranked by heat, canopy, and income, a city can identify the specific areas where new trees or cool surfaces would have the largest effect.
I combined satellite thermal imagery, land-cover data, and census income into one dataset: summer surface temperature, tree canopy, impervious cover, and median income for each of Austin's 65 neighborhood planning areas. Surface heat tracks canopy and pavement closely and income moderately. Since canopy and pavement can be changed, the same data shows a city where tree planting and cool-surface projects would reduce heat the most.
Data & methods. Land surface temperature: median of clear-sky Landsat 8 & 9 thermal scenes (June–August 2022–2024), processed in Google Earth Engine. Tree canopy and impervious surface: NLCD / USFS products, zonal means per neighborhood. Boundaries: City of Austin Neighborhood Planning Areas (65, dissolved from the open-data layer). Income: U.S. Census ACS 2018–2022 (table B19013), area-weighted from census tracts to neighborhoods via a PostGIS spatial join (tracts reprojected NAD83→WGS84; geometries validated before overlay). Correlations computed across all 65 planning areas (n = 65). Charts built with Chart.js; map with Leaflet. Full methodology →