Standardized Precipitation Index Table

Northeast Climate Division

Illinois, Climate Division 02

Precipitation Data Table

Time Scale in Months (As of the end of Jun. 2020)
1 2 3 4 5 6 7 8 9 10 11 12 15 18 24 30 36 48 60 72
Accumulated Precipitation (in.) 3.43 10.25 14.84 18.13 18.92 21.87 23.63 25.22 30.76 40.01 43.26 47.55 64.63 72.19 92.19 113.15 133.13 177.28 216.62 255.16
Accumulated Precipitation Departure from Normal (in.) -0.61 2.27 3.48 4.28 3.56 4.76 4.5 3.71 6.52 12.27 11.92 12.59 18.34 20.16 22.35 26.3 28.51 37.93 42.58 46.4
Accumulated Precipitation Percent of Average 85 128 131 131 123 128 124 117 127 144 138 136 140 139 132 130 127 127 124 122
Accumulated Precipitation Percentile (non-exceedance) 42.4 82 85.6 88.2 84 88.7 86.2 81.2 92.3 98.7 98.2 98.1 99.5 99.7 99.5 99.7 99.5 99.8 99.8 99.8
Standardized Precipitation Index -0.19 0.92 1.06 1.19 0.99 1.21 1.09 0.88 1.43 2.24 2.1 2.07 2.55 2.71 2.58 2.75 2.58 2.89 2.87 2.81