The Illinois Agronomy Handbook recommends that fall N applications should be done when the daily maximum bare soil temperature at 4 inches is below 50 degrees. Fall application is not recommended south of Illinois Highway 16.
The Illinois State Water Survey’s Water and Atmospheric Resource Monitoring (WARM) program has a network of 19 sites around Illinois with daily soil temperature readings at 4 and 8 inches. You can see the reports from “yesterday” on their soil temperature page. Be sure to look at the daily maximum 4-inch bare soil temperature.
As of this writing (November 4), the daily maximum 4-inch bare soil temperature is below 50 degrees in the northwest part of the state. However, it is still in the low to mid 50s across northeastern and much of central Illinois.
Of course, the soil temperature in a particular field can vary due to the temperature, soil moisture, vegetation and tillage, and even soil color.
The figure below shows the average date when the 4-inch soil temperature reached 50 degrees in the fall. In general the average date was in mid-November. However, it can vary from year to year depending on weather and soil conditions.
Dry October in Illinois
Precipitation
The statewide average precipitation for October in Illinois was 1.79 inches, 1.12 inches below average or 61 percent of average. That makes it the 21st driest October on record back to 1895. See map below.
Amounts of less than an inch were common in western Illinois. The driest spot for October in Illinois was Colchester (near Macomb) with 0.22 inches for the month. The wettest spot in Illinois was Lansing (south Chicago) with 5.22 inches.
Moderate to severe drought remains in western Illinois, according to the U.S. Drought Monitor. The National Weather Service has predicted above-average precipitation for November across Illinois. Combined with cooler temperatures, this should lead to improvements in that area of the state.
Temperature
The statewide average temperature for October in Illinois was 55.1 degrees, just 0.5 degrees above average. The highest temperature for October in Illinois was 92 degrees at Bentley on October 8. The lowest temperature was 23 degrees at Mt. Carroll on October 29. Most of Illinois experienced temperatures at or below freezing by the end of the month.
Snowfall
No measurable snow reported yet. I’m sure that will change in November.
