Fairfax Climate

Heat across Fairfax County

The study brings local climate and building data into one geographic comparison. It tests where surface temperatures rise and how those places differ in vegetation and developed land cover.

Data and methods

Sources used in the analysis:

• Fairfax land surface temperature. Landsat-derived summer LST inside the fairfax_climate pack, aggregated to county, tract, block group, and block scales.
• Fairfax buildings. Local building footprints and use types inside the fairfax_climate pack.
• Impervious-surface context. NLCD Annual Impervious Surface (MRLC / USGS), 30 m resolution, in the fairfax_climate pack. Fractional impervious percentage and road/urban/non-urban descriptor classes, 1985–2024 annual series.

The workflow clipped all layers to Fairfax County, aligned them to a shared geography, calculated NDVI from Landsat spectral bands, and derived land surface temperature from Landsat thermal bands with emissivity correction. High-temperature areas were then compared against impervious surface and vegetation patterns, with a supporting regression sheet testing how surface temperature changes with distance from denser urban centers.

Findings

The clearest hot zones sit in the more urbanized eastern and central portions of Fairfax County, while the western side stays cooler where vegetation cover is stronger and development density is lower. The supporting regression shows a negative relationship between surface temperature and distance from urban centers, but it is weak (R2 = 0.14), which fits the broader conclusion: heat patterns are shaped by several land-cover and built-environment factors, not a single driver.