Ill., soils are cooling in the first half of Oct.

Soil temperatures have fallen 10 to 20 degrees so far in Oct., which is normal for this time of year, according to Jennie Atkins, Water and Atmospheric Resources Monitoring (WARM) program manager at the Illinois State Water Survey.

Soil temperatures have dropped the first half of this month as fall weather moved into the state. Temperatures at four inches under sod averaged 59 degrees on Oct. 15, or 12 degrees cooler than on Oct. 1 and equal to the long-term average. Highs reached the mid-60s with lows in the 50s.

Under bare soil, temperatures have fallen further with a 16-degree drop so far this month. Temperatures at 4 inches under bare soil averaged 56 degrees on Oct. 15, with highs in the mid-60s and lows in the 40s.

Rain at the end of the second week led to increasing soil moisture at the shallower depths in northern and central Illinois. On average, 2-inch moisture levels rose 24 percent in October. The highest increases were in the west where levels increased 59 percent. Smaller increases were seen in eastern and northern Illinois. Levels remained steady in the south.

Soil moisture increases occurred through 8 inches of soil. At depths of 20 inches and greater, there was little overall change statewide.

The Ill. State Water Survey’s 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 website (warm.isws.illinois.edu/warm).