4-Inch Soil Temperature in New Hampshire
The current average 4-inch soil temperature across New Hampshire is 56°F, measured at 3 USDA and NOAA monitoring stations. Readings range from 53°F to 58°F. Soil across New Hampshire is running 3°F below the seasonal normal of 59°F for late September, based on 3 of 3 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 New Hampshire (3)
| Station | 4" Temp | Last Reading |
|---|---|---|
| Hubbard Brook (Grafton) | 53°F | 2026-09-23 |
| Durham 2 N | 57°F | 2026-09-23 |
| Durham 2 SSW | 58°F | 2026-09-23 |
Cities in New Hampshire (11)
4-Inch Soil Temperature FAQ for New Hampshire
What is the current 4-inch soil temperature in New Hampshire?
The current average 4-inch soil temperature across New Hampshire is 56°F, measured at 3 USDA and NOAA stations. Readings range from 53°F to 58°F depending on location and elevation. Soil across New Hampshire is running 3°F below the seasonal normal of 59°F for late September, based on 3 of 3 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 New Hampshire soil temperature directory (all depths), the national soil temperature by depth comparison, or the live national soil temperature map.