4-Inch Soil Temperature in Alaska
The current average 4-inch soil temperature across Alaska is 40°F, measured at 2 USDA and NOAA monitoring stations. Readings range from 34°F to 46°F. Soil across Alaska is running 2°F above the seasonal normal of 38°F for early October, based on 2 of 2 stations with historical records. Last updated September 29, 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 Alaska (2)
| Station | 4" Temp | Last Reading |
|---|---|---|
| Kanuti Lake (Yukon-Koyukuk) | 34°F | 2026-09-29 |
| Kenai 29 ENE | 46°F | 2026-09-29 |
Cities in Alaska (8)
4-Inch Soil Temperature FAQ for Alaska
What is the current 4-inch soil temperature in Alaska?
The current average 4-inch soil temperature across Alaska is 40°F, measured at 2 USDA and NOAA stations. Readings range from 34°F to 46°F depending on location and elevation. Soil across Alaska is running 2°F above the seasonal normal of 38°F for early October, based on 2 of 2 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 Alaska soil temperature directory (all depths), the national soil temperature by depth comparison, or the live national soil temperature map.