Standardized Precipitation Index Table

Southeast Climate Division

Illinois, Climate Division 09

Precipitation Data Table

Time Scale in Months (As of the end of Jul. 2026)
1 2 3 4 5 6 7 8 9 10 11 12 15 18 24 30 36 48 60 72
Accumulated Precipitation (in.) 5.74 10.42 14.04 17.51 22.64 23.29 24.22 25.32 27.4 31.51 34.28 35.08 49.44 64.62 84.23 107.15 124.43 164.35 209.44 256.8
Accumulated Precipitation Departure from Normal (in.) 1.88 2.52 1.67 0.8 1.58 -0.65 -3.11 -5.5 -7 -6 -6.55 -9.19 -7.19 -3.6 -4.41 -5.39 -8.5 -12.88 -12.12 -9.13
Accumulated Precipitation Percent of Average 149 132 113 105 108 97 89 82 80 84 84 79 87 95 95 95 94 93 95 97
Accumulated Precipitation Percentile (non-exceedance) 85.8 83.1 69.5 60.3 64.4 48.6 32.5 20.4 15.4 20.6 18.7 11.3 19.9 36.5 36.3 34.6 28 21.4 25.3 32.9
Standardized Precipitation Index 1.07 0.96 0.51 0.26 0.37 -0.03 -0.45 -0.83 -1.02 -0.82 -0.89 -1.21 -0.85 -0.35 -0.35 -0.4 -0.58 -0.79 -0.66 -0.44