Standardized Precipitation Index Table

Northeast Climate Division

Illinois, Climate Division 02

Precipitation Data Table

Time Scale in Months (As of the end of Mar. 2024)
1 2 3 4 5 6 7 8 9 10 11 12 15 18 24 30 36 48 60 72
Accumulated Precipitation (in.) 3.87 4.47 7.79 10.57 11.5 15.35 19.41 21.83 28.63 30.45 32.16 34.73 43.05 48.63 71.41 86.5 103.48 138.71 188.42 230.13
Accumulated Precipitation Departure from Normal (in.) 1.36 0.45 2.01 2.8 1.39 2.48 3.05 1.9 5.04 2.84 0.63 -0.15 2.4 0.84 1.58 3.81 -1.23 -0.95 13.81 20.65
Accumulated Precipitation Percent of Average 154 111 135 136 114 119 119 110 121 110 102 100 106 102 102 105 99 99 108 110
Accumulated Precipitation Percentile (non-exceedance) 86.3 66 86.2 89.3 72 80.9 80.2 69.7 86.6 72.8 56.9 51 67.4 57 59.5 68.6 46.2 48 83.7 90
Standardized Precipitation Index 1.1 0.41 1.09 1.24 0.58 0.87 0.85 0.52 1.11 0.61 0.17 0.03 0.45 0.18 0.24 0.48 -0.09 -0.05 0.98 1.28