June 27, 2022

Soils are dry with warmer weather in May

CHAMPAIGN, Ill. — Hotter weather in the first half of May has caused warmer, drier soils across Illinois, according to Jennie Atkins, Water and Atmospheric Resources Monitoring program manager at the Illinois State Water Survey.

Illinois has seen warmer than normal weather this May with temperatures rising to the 90s across the state in the second week of the month. The warmer weather has led to hotter soils.

Soil temperatures at 4 inches under bare soil rose 12 degrees so far in May to a state average of 70 degrees on May 16, 6 degrees higher than last year’s average and 5 degrees warmer than the historical average. Daily highs were in the mid-70s to the mid-80s.

The higher soil temperatures combined with limited rainfall in the second week of the month caused soil moisture levels to decline at depths from 2 to 8 feet. Two-inch moisture levels averaged 0.25 water fraction by volume on May 16, a decrease of 30% from May 1.

While soils have been drying throughout the state, the largest declines were seen in northern and eastern Illinois where levels were 39% and 38% lower, respectively. Despite the drying, soil moisture remains above the wilting points at the soils monitored.

Moisture levels at 4 and 8 feet declined 20% and 11%, respectively. At the deeper depths, soil moisture remained high, showing little change over the first half of May.

The Illinois 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, www.isws.illinois.edu/warm.