Precipitation varied greatly across the Illinois Climate
Network (ICN) in the first two weeks of August with totals
ranging from 0.06 inches in Freeport (Stephenson County) to 2.92
inches at the Rend Lake station near Ina (Jefferson County).
But despite the differences in rainfall totals, soil moisture
levels showed no significant overall changes in the first half
of the month. Levels at depths of 2 inches averaged 0.24 water
fraction by volume (wfv) on August 15 with regional averages
ranging from 0.27 wfv in southern Illinois to 0.20 wfv in the
west-central part of the state.
Moisture increases were seen at the deeper depths. On August 15,
soil moisture averaged 0.35 wfv at 20 inches and 0.44 wfv at 59
inches, 7 to 17 percent above the long-term average.
Soil temperatures were slightly above normal in the first half
of the month. Temperatures at 4 inches under bare soil averaged
80.4 degrees, though recorded temperatures ranged from 62.5 to
98.9.
Soil temperatures under sod were 2 to 3 degrees cooler with
averages of 78.0 degrees and 77.1 at depths of 4 and 8 inches,
respectively.
[Lisa A. Sheppard, Illinois State
Water Survey]
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