Standardized Precipitation Index Table

Powder, Little Missouri, Tongue Climate Division

Wyoming, Climate Division 05

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.) 0.29 1.11 1.37 4.18 4.89 5.81 8.05 9.53 12.52 14.67 15.99 16.37 17.68 20.08 28.27 35.31 47.14 62.67 73.91 83.56
Accumulated Precipitation Departure from Normal (in.) -0.33 -0.13 -0.61 1 0.46 0.4 1.27 0.49 0.87 1.2 1.45 1.2 0.54 -0.48 -2.04 -0.4 1.66 2.02 -1.9 -7.43
Accumulated Precipitation Percent of Average 47 90 69 131 110 107 119 105 107 109 110 108 103 98 93 99 104 103 97 92
Accumulated Precipitation Percentile (non-exceedance) 13.4 43.6 17.8 85.6 67.2 64.3 78.9 62 65.5 68.9 71.2 68.2 59.3 46.3 32.2 48.1 64 64.1 40.4 17.3
Standardized Precipitation Index -1.11 -0.16 -0.92 1.06 0.44 0.37 0.8 0.3 0.4 0.49 0.56 0.47 0.24 -0.09 -0.46 -0.05 0.36 0.36 -0.24 -0.94