Most of Illinois has warmer, drier soils in mid-September

[September 25, 2019]    Warmer weather has caused higher than normal soil temperatures for Illinois, according to Jennie Atkins, Water and Atmospheric Resources Monitoring (WARM) Program manager at the University of Illinois’ Illinois State Water Survey.

Soil temperatures at 4 inches under sod averaged 74 degrees on Sept. 15, 4 degrees warmer than the long-term average for the middle of September. Temperatures were near normal the first week but rose the second as the state experienced warmer weather. Daily highs ranged from the mid-70s to the low 90s.

Temperatures were warmer under bare soil, averaging 75 degrees on Sept. 15 at 4-inch depths. Soil temperatures peaked on September 12 with daily highs in the 80s in northern Illinois and in the 90s for the central and southern regions. Temperatures have fallen 5 degrees on average since that point but remain warmer than normal.

Soil moisture has fallen for most of the state in September. Moisture levels at 2 inches fell an average of 13 percent over the first half of the month. The largest declines were in southern Illinois, which had both the highest soil temperatures and lowest rainfall totals. Northern Illinois was the only region with increasing soil moisture, as the area had significantly higher than normal rain the first half of the month.

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 

[LISA A SHEPHERD]