4-Inch Soil Temperature in Kentucky
The current average 4-inch soil temperature across Kentucky is 73°F, measured at 3 USDA and NOAA monitoring stations. Readings range from 73°F to 74°F. Soil across Kentucky is running 3°F above the seasonal normal of 70°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 Kentucky (3)
| Station | 4" Temp | Last Reading |
|---|---|---|
| Princeton #1 (Caldwell) | 73°F | 2026-09-23 |
| Mammoth Cave (Hart) | 73°F | 2026-09-23 |
| Bowling Green 21 NNE | 74°F | 2026-09-23 |
Cities in Kentucky (37)
| City | ZIP | Current Temp |
|---|---|---|
| Ashland | 41101 | — |
| Berea | 40403 | — |
| Bowling Green | 42101 | 74°F |
| Campbellsville | 42718 | 73°F |
| Corbin | 40701 | — |
| Covington | 41011 | — |
| Danville | 40422 | 73°F |
| Elizabethtown | 42701 | 73°F |
| Erlanger | 41018 | — |
| Florence | 41022 | — |
| Fort Knox | 40121 | 74°F |
| Frankfort | 40601 | 73°F |
| Franklin | 42134 | 74°F |
| Glasgow | 42141 | 73°F |
| Hazard | 41701 | — |
| Hebron | 41021 | — |
| Henderson | 42419 | 73°F |
| Hopkinsville | 42240 | 73°F |
| La Grange | 40031 | 73°F |
| Lancaster | 40444 | 73°F |
| Leitchfield | 42754 | 74°F |
| Lexington | 40502 | — |
| London | 40741 | — |
| Louisville | 40201 | 74°F |
| Newport | 41071 | — |
| Nicholasville | 40340 | 73°F |
| Owensboro | 42301 | 73°F |
| Paducah | 42001 | 73°F |
| Paris | 40361 | — |
| Pikeville | 41501 | — |
| Radcliff | 40159 | 74°F |
| Richmond | 40475 | — |
| Shelbyville | 40065 | 73°F |
| Shepherdsville | 40165 | 73°F |
| Somerset | 42501 | 73°F |
| Versailles | 40383 | 73°F |
| Winchester | 40391 | — |
4-Inch Soil Temperature FAQ for Kentucky
What is the current 4-inch soil temperature in Kentucky?
The current average 4-inch soil temperature across Kentucky is 73°F, measured at 3 USDA and NOAA stations. Readings range from 73°F to 74°F depending on location and elevation. Soil across Kentucky is running 3°F above the seasonal normal of 70°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 Kentucky soil temperature directory (all depths), the national soil temperature by depth comparison, or the live national soil temperature map.