4-Inch Soil Temperature in Illinois
The current average 4-inch soil temperature across Illinois is 67°F, measured at 3 USDA and NOAA monitoring stations. Readings range from 62°F to 71°F. Soil across Illinois is right at the seasonal normal of 66°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 Illinois (3)
| Station | 4" Temp | Last Reading |
|---|---|---|
| Mason #1 (Mason) | 71°F | 2026-09-22 |
| Champaign 9 SW | 68°F | 2026-09-23 |
| Shabbona 5 NNE | 62°F | 2026-09-23 |
Cities in Illinois (62)
| City | ZIP | Current Temp |
|---|---|---|
| Arlington Heights | 60004 | 62°F |
| Aurora | 60502 | 62°F |
| Barrington | 60010 | 62°F |
| Belleville | 62220 | — |
| Bensenville | 60105 | 62°F |
| Bloomingdale | 60108 | 62°F |
| Bloomington | 61701 | 68°F |
| Bolingbrook | 60440 | 62°F |
| Carbondale | 62901 | — |
| Carol Stream | 60116 | 62°F |
| Champaign | 61820 | 68°F |
| Chicago | 60290 | 62°F |
| Chicago Heights | 60411 | 62°F |
| Crystal Lake | 60012 | 62°F |
| Danville | 61832 | 68°F |
| Decatur | 62521 | 68°F |
| Des Plaines | 60016 | 62°F |
| Downers Grove | 60515 | 62°F |
| East Peoria | 61611 | 71°F |
| East Saint Louis | 62201 | — |
| Edwardsville | 62025 | — |
| Elgin | 60120 | 62°F |
| Elk Grove Village | 60007 | 62°F |
| Evanston | 60201 | 62°F |
| Fox Valley | 60597 | 62°F |
| Galesburg | 61401 | 71°F |
| Glen Ellyn | 60137 | 62°F |
| Glenview | 60025 | 62°F |
| Hinsdale | 60521 | 62°F |
| Hoffman Estates | 60169 | 62°F |
| Jacksonville | 62650 | 71°F |
| Joliet | 60431 | 62°F |
| Libertyville | 60048 | 62°F |
| Loves Park | 61111 | 62°F |
| Mascoutah | 62224 | — |
| Mchenry | 60050 | 62°F |
| Melrose Park | 60160 | 62°F |
| Moline | 61265 | 71°F |
| Naperville | 60540 | 62°F |
| Normal | 61761 | 68°F |
| North Chicago | 60064 | 62°F |
| Northbrook | 60062 | 62°F |
| Oak Lawn | 60453 | 62°F |
| Oak Park | 60301 | 62°F |
| Orland Park | 60462 | 62°F |
| Palatine | 60038 | 62°F |
| Pekin | 61554 | 71°F |
| Peoria | 61601 | 71°F |
| Plainfield | 60544 | 62°F |
| Quincy | 62301 | 71°F |
| Rock Island | 61201 | 71°F |
| Rockford | 61101 | 62°F |
| Saint Charles | 60174 | 62°F |
| Schaumburg | 60159 | 62°F |
| Skokie | 60076 | 62°F |
| Springfield | 62701 | 71°F |
| Tinley Park | 60477 | 62°F |
| Urbana | 61801 | 68°F |
| Waukegan | 60079 | 62°F |
| West Chicago | 60185 | 62°F |
| Wheaton | 60187 | 62°F |
| Wood Dale | 60191 | 62°F |
4-Inch Soil Temperature FAQ for Illinois
What is the current 4-inch soil temperature in Illinois?
The current average 4-inch soil temperature across Illinois is 67°F, measured at 3 USDA and NOAA stations. Readings range from 62°F to 71°F depending on location and elevation. Soil across Illinois is right at the seasonal normal of 66°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 Illinois soil temperature directory (all depths), the national soil temperature by depth comparison, or the live national soil temperature map.