4-Inch Soil Temperature in California
The current average 4-inch soil temperature across California is 77°F, measured at 24 USDA and NOAA monitoring stations. Readings range from 54°F to 99°F. Soil across California is running 2°F above the seasonal normal of 75°F for late September, based on 24 of 24 stations with historical records. Last updated September 23, 2026.
Why the 4-Inch Reading
Every reading here is measured at native 4-inch depth by USDA SCAN (Soil Climate Analysis Network) and NOAA USCRN (US Climate Reference Network) stations, not modeled. The 4-inch root-zone temperature changes more slowly than the surface, making it the steadier signal for established-lawn and garden timing: pre-emergent and broadleaf herbicide windows, fertilizer applications, and core aeration.
Stations Measuring 4-Inch Depth in California (24)
| Station | 4" Temp | Last Reading |
|---|---|---|
| Marble Creek (Mono) | 69°F | 2026-09-23 |
| Desert Center (Riverside) | 96°F | 2026-09-23 |
| Ford Dry Lake (Riverside) | 94°F | 2026-09-23 |
| Essex (San Bernardino) | 87°F | 2026-09-23 |
| Shadow Mtns (San Bernardino) | 78°F | 2026-09-23 |
| Deep Springs (Inyo) | 72°F | 2026-09-23 |
| Cochora Ranch (San Luis Obispo) | 82°F | 2026-09-23 |
| Death Valley Jct (Inyo) | 83°F | 2026-09-23 |
| Doe Ridge (Mono) | 66°F | 2026-09-23 |
| Eagle Lake (Lassen) | 63°F | 2026-09-23 |
| Bodie Hills (Mono) | 54°F | 2026-09-23 |
| Monocline Ridge (Fresno) | 89°F | 2026-09-23 |
| French Gulch (Shasta) | 77°F | 2026-09-23 |
| Stubblefield (San Luis Obispo) | 80°F | 2026-09-23 |
| Vallecitos (San Benito) | 80°F | 2026-09-23 |
| Adobe (Mono) | 65°F | 2026-09-23 |
| Rancheria (Mono) | 63°F | 2026-09-23 |
| Chimney Creek (Tulare) | 66°F | 2026-09-23 |
| Redding 12 WNW | 82°F | 2026-09-23 |
| Stovepipe Wells 1 SW | 99°F | 2026-09-23 |
| Yosemite Village 12 W | 70°F | 2026-09-23 |
| Fallbrook 5 NE | 83°F | 2026-09-23 |
| Santa Barbara 11 W | 75°F | 2026-09-23 |
| Merced 23 WSW | 72°F | 2026-09-23 |
Cities in California (314)
4-Inch Soil Temperature FAQ for California
What is the current 4-inch soil temperature in California?
The current average 4-inch soil temperature across California is 77°F, measured at 24 USDA and NOAA stations. Readings range from 54°F to 99°F depending on location and elevation. Soil across California is running 2°F above the seasonal normal of 75°F for late September, based on 24 of 24 stations with historical records.
What does the 4 inch soil temperature mean?
The 4 inch soil temperature shows conditions deeper in the root zone than the 2 inch germination reading. It is commonly used for established lawn, garden, and agricultural timing because it changes more slowly than the surface layer, so it is a steadier signal for fertilizer, aeration, and weed-control decisions.
Why use 4-inch soil temperature instead of 2-inch?
Use 2 inches for germination decisions, since that is where seeds sit. Use the 4 inch soil temperature for established lawn and garden timing: it reads the root zone, changes more slowly than the surface, and is the depth most fertilizer, aeration, and disease guidance references.
See the national 4-inch soil temperature map, the full California soil temperature directory (all depths), the national soil temperature by depth comparison, or the live national soil temperature map.