CHAMPAIGN, Ill., 9/17/21: Soils remained warm in mid-September because of hotter than normal weather across Illinois, according to Jennie Atkins, Water and Atmospheric Resources Monitoring (WARM) program manager at the Illinois State Water Survey.
Soil temperatures at 4 inches under sod averaged 74 degrees on Sept. 15, 3 degrees warmer than last year and 4 degrees higher than the long-term average. Soils have cooled 3 degrees since Sept. 1, despite rising in the second week. Daily highs on Sept. 15 reached into the 70s and low 80s with lows in the 60s to mid-70s.
Under bare soil, 4-inch temperatures were also warmer than normal, averaging 76 degrees on Sept. 15 or 10 degrees higher than the long-term average. Daily highs were in the 80s.
Soil moisture has declined throughout the state in September. Levels at 4 inches have dropped 13 percent since Sept. 1 to a statewide average of 0.21 water fraction by volume (wfv). While declines were seen in all regions, northern Illinois soils averaged 0.15 wfv on Sept. 15, near the wilting points for the soils monitored. Northern Illinois soils have also been drying at 8 inches as levels fell 21 percent in the first half of the month to an average of 0.14 wfv.
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 (http://www.isws.illinois.edu/warm/) and in the Illinois Water and Climate Summary (http://www.isws.illinois.edu/warm/climate.asp).
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Media contact: Jennie Atkins, Ph.D., 217-333-4966, jatkins@illinois.edu
news@prairie.illinois.edu
