Standardized Precipitation Index Table

Western Climate Division

Montana, Climate Division 01

Precipitation Data Table

Time Scale in Months (As of the end of Feb. 2024)
1 2 3 4 5 6 7 8 9 10 11 12 15 18 24 30 36 48 60 72
Accumulated Precipitation (in.) 2.31 5.02 7.22 10.12 11.65 13.25 15.68 15.96 18.64 21.71 23.44 25.28 33.19 40.1 54.13 71.9 81.69 112.38 141.07 169.39
Accumulated Precipitation Departure from Normal (in.) -0.53 -1.56 -2.86 -3.57 -4.47 -4.75 -3.64 -4.63 -4.82 -4.49 -5.03 -5.94 -8.16 -9.18 -8.39 -8.66 -12.1 -12.6 -15.11 -17.99
Accumulated Precipitation Percent of Average 81 76 72 74 72 74 81 78 79 83 82 81 80 81 87 89 87 90 90 90
Accumulated Precipitation Percentile (non-exceedance) 38 24.8 16.4 16.3 11.6 11.5 18.9 12.5 12.9 17.4 14.6 9.9 6.3 6.9 11.5 14 7.6 10 8.2 6.1
Standardized Precipitation Index -0.3 -0.68 -0.98 -0.98 -1.2 -1.2 -0.88 -1.15 -1.13 -0.94 -1.05 -1.29 -1.53 -1.48 -1.2 -1.08 -1.43 -1.28 -1.4 -1.54