Standardized Precipitation Index Table

South Central Climate Division

Montana, Climate Division 05

Precipitation Data Table

Time Scale in Months (As of the end of Apr. 2026)
1 2 3 4 5 6 7 8 9 10 11 12 15 18 24 30 36 48 60 72
Accumulated Precipitation (in.) 1.48 2.92 3.63 3.94 5.92 6.54 9.37 10.51 11.53 13.24 15.36 18.09 24.28 27.01 37.37 42.87 58.82 77.14 91.07 107.16
Accumulated Precipitation Departure from Normal (in.) -0.35 -0.21 -0.41 -1.11 -0.08 -0.53 0.88 0.51 0.36 0.73 0.33 0.34 2.48 2.17 1.86 0.29 5.56 6.15 2.38 0.76
Accumulated Precipitation Percent of Average 81 93 90 78 99 93 110 105 103 106 102 102 111 109 105 101 110 109 103 101
Accumulated Precipitation Percentile (non-exceedance) 37.5 44.3 36.7 16.6 50.5 38.3 72.6 62.9 59.5 65.2 57.4 56.7 80.2 75.4 67.7 53.9 84.3 82.4 63.3 54.6
Standardized Precipitation Index -0.32 -0.14 -0.34 -0.97 0.01 -0.3 0.6 0.33 0.24 0.39 0.19 0.17 0.85 0.69 0.46 0.1 1.01 0.93 0.34 0.12