Cooler, drier weather has led to declining soil temperatures and moisture levels, according to Jennie Atkins, Water and Atmospheric Resources Monitoring Program manager at the Illinois State Water Survey, part of the Prairie Research Institute at Illinois.
The first half of March has been cooler and drier than normal. Air temperatures have declined overall from a state average of 45.3 degrees on March 1 to 36.8 degrees on March 14. Soil temperatures have also followed this trend. Temperatures at depths of 4 inches under bare soil averaged 38.4 degrees on March 14, 8.5 degrees cooler than on March 1 and 1.3 degrees below the long-term average.
Soils throughout the state have thawed, with temperatures ranging from daily highs in the 40s and 50s to lows in the 30s.
Moisture levels have also been declining as soils dry after February’s record-breaking rain. Soil moisture at 4 inches averaged 0.34 water fraction by volume on March 14, a decrease of 12 percent from the beginning of the month. However, despite the drying, several stations are still reporting moisture levels near or above the field capacity.
The 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 and in the Illinois Water and Climate Summary.