CHAMPAIGN, Ill. - With the arrival of spring, Illinois farmers are monitoring soil temperatures for decisions in the field. Soil temperatures across the state have been on the rise, according to State Climatologist Jim Angel of the Illinois State Water Survey (ISWS), University of Illinois at Urbana-Champaign.

The ISWS Water and Atmospheric Resources Monitoring (WARM) Program records soil temperatures at 4 and 8 inches under grass at 19 sites across the state. In addition, 4-inch bare soil temperatures are computed to represent a cultivated field. These data are available in map and tabular form for the past 7 days at http://www.isws.illinois.edu/warm/soiltemp.asp.

Currently, the 4-inch soil temperatures under grass during the day are into the upper 40s in northern Illinois, the low to mid 50s in central Illinois, and the mid 50s in southern Illinois. At night they are cooling off by about 4 to 6 degrees.

“The statewide soil temperatures give a general idea of conditions; however, soil temperatures in an individual field will depend on factors such as soil moisture and tillage practices,” Angel said. “Also, soil temperatures at the surface will warm up and cool off much faster than in deeper layers.”

The Illinois State Water Survey, a division of the Institute of Natural Resource Sustainability at the University of Illinois at Urbana-Champaign, is the primary agency in Illinois concerned with water and atmospheric resources.