Cooler weather has caused soil temperatures to decrease across the state, according to Jennie Atkins, Water and Atmospheric Resources Monitoring Program manager at the Illinois State Water Survey at Illinois.
Air temperatures fell 34 degrees over the past week, from a state average of 76 degrees on Oct. 9 to 42 degrees on Oct. 15. Soil temperatures followed with declines from 11 degrees at depths of 8 inches under sod to 22 degrees at 2 inches under bare soil. On Oct. 15, temperatures averaged in the 50s, or 2 to 4 degrees cooler than in October 2017.
Soil moisture has risen for most of Illinois in October. The state has received 2.93 inches of rain so far this month, 1.57 inches higher than normal. Moisture levels at 2-inch depths increased 15 percent on average.
The largest increases were in western Illinois, where levels rose 64 percent. Double-digit moisture-level rises also occurred in the northern and eastern regions. The southern part of the state, however, has had lower-than-normal rainfall in October, resulting in the soil moisture declining 12 percent.
Moisture levels statewide increased at depths to 20 inches, but remained steady at 39 and 59 inches.
The WARM Program collects hourly and daily weather and soil information at 19 stations across the state. Daily and monthly summaries can be found at the WARM websiteand in the Illinois Water and Climate Summary.