4-Inch Soil Temperature in Idaho
The current average 4-inch soil temperature across Idaho is 68°F, measured at 4 USDA and NOAA monitoring stations. Readings range from 63°F to 73°F. Soil across Idaho is running 5°F above the seasonal normal of 63°F for late September, based on 4 of 4 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 Idaho (4)
| Station | 4" Temp | Last Reading |
|---|---|---|
| Jordan Valley Cwma (Owyhee) | 71°F | 2026-09-23 |
| Orchard Range Site (Ada) | 73°F | 2026-09-23 |
| Arco 17 SW | 63°F | 2026-09-23 |
| Murphy 10 W | 64°F | 2026-09-23 |
Cities in Idaho (12)
| City | ZIP | Current Temp |
|---|---|---|
| Boise | 83701 | 73°F |
| Caldwell | 83605 | 64°F |
| Coeur D Alene | 83814 | — |
| Idaho Falls | 83401 | 63°F |
| Meridian | 83642 | 73°F |
| Moscow | 83843 | — |
| Nampa | 83651 | 64°F |
| Pocatello | 83201 | 63°F |
| Post Falls | 83854 | — |
| Rexburg | 83440 | 63°F |
| Sun Valley | 83353 | 63°F |
| Twin Falls | 83301 | 63°F |
4-Inch Soil Temperature FAQ for Idaho
What is the current 4-inch soil temperature in Idaho?
The current average 4-inch soil temperature across Idaho is 68°F, measured at 4 USDA and NOAA stations. Readings range from 63°F to 73°F depending on location and elevation. Soil across Idaho is running 5°F above the seasonal normal of 63°F for late September, based on 4 of 4 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 Idaho soil temperature directory (all depths), the national soil temperature by depth comparison, or the live national soil temperature map.