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 Jul. 2026)
1 2 3 4 5 6 7 8 9 10 11 12 15 18 24 30 36 48 60 72
Accumulated Precipitation (in.) 1.05 2.62 3.84 5.31 5.94 6.2 6.45 7.22 7.48 10.29 11 11.92 18.63 22.48 26.19 34.38 41.42 59.37 73.68 83.56
Accumulated Precipitation Departure from Normal (in.) -0.32 -1 -2.39 -2.73 -3.17 -3.53 -3.9 -3.74 -4.22 -2.61 -3.15 -3.21 -2.74 -2.41 -4.09 -5.65 -4.02 -1.25 -2.08 -7.37
Accumulated Precipitation Percent of Average 77 72 62 66 65 64 62 66 64 80 78 79 87 90 87 86 91 98 97 92
Accumulated Precipitation Percentile (non-exceedance) 37.2 25.2 10.2 8.5 6.1 4.1 3.2 4.3 2.8 15.5 11.3 11.3 21.7 26.4 15.9 11.3 22 42.9 39.1 16.8
Standardized Precipitation Index -0.33 -0.67 -1.27 -1.37 -1.55 -1.74 -1.85 -1.72 -1.92 -1.01 -1.21 -1.21 -0.78 -0.63 -1 -1.21 -0.77 -0.18 -0.28 -0.96