Standardized Precipitation Index Table

Central Climate Division

Montana, Climate Division 04

Precipitation Data Table

Time Scale in Months (As of the end of Jan. 2026)
1 2 3 4 5 6 7 8 9 10 11 12 15 18 24 30 36 48 60 72
Accumulated Precipitation (in.) 0.36 2.17 2.82 4.36 5.09 6.54 8.87 11.14 13.73 14.99 15.93 17.2 19.8 24.11 34 40.61 53.07 70.66 82.87 98.72
Accumulated Precipitation Departure from Normal (in.) -0.62 0.2 -0.14 0.24 -0.51 -0.41 0.35 -0.41 -0.54 -0.79 -0.97 -0.55 -0.92 -0.6 -1.51 -1.84 -0.19 -0.31 -5.77 -7.64
Accumulated Precipitation Percent of Average 37 110 95 106 91 94 104 96 96 95 94 97 96 98 96 96 100 100 93 93
Accumulated Precipitation Percentile (non-exceedance) 6.8 64.6 49.4 61.5 40.6 43.6 59.9 46.1 45.1 41.6 39.3 44.9 40.8 45.1 37.6 35.7 49.9 49.1 20.7 16.4
Standardized Precipitation Index -1.49 0.37 -0.01 0.29 -0.24 -0.16 0.25 -0.1 -0.12 -0.21 -0.27 -0.13 -0.23 -0.12 -0.31 -0.37 0 -0.02 -0.82 -0.98