4-Inch Soil Temperature by State

The current average 4-inch soil temperature across the US is 80°F, measured at 307 USDA SCAN and NOAA USCRN stations reporting at native 4-inch depth. The 4-inch (root-zone) reading sits below the 2-inch germination layer, changes more slowly, and is the depth most fertilizer, aeration, and weed-control timing references. Every reading here is measured, not modeled — the provenance no modeled-only soil map can match.