Standardized Precipitation Index Table

Cheyenne & Niobrara Climate Division

Wyoming, Climate Division 07

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.) 1.16 1.38 1.59 1.73 2.15 2.45 4.41 6.11 7.15 9.52 12.07 14.57 17.4 18.4 25.56 28.81 42.71 54.66 67.97 77.8
Accumulated Precipitation Departure from Normal (in.) -0.5 -1.07 -1.35 -1.63 -1.66 -1.89 -0.9 -0.32 -0.48 0.09 0.4 0.33 0.21 -0.18 -2.9 -4 0 -2.3 -3.27 -7.71
Accumulated Precipitation Percent of Average 70 56 54 51 56 56 83 95 94 101 103 102 101 99 90 88 100 96 95 91
Accumulated Precipitation Percentile (non-exceedance) 30.4 8.8 4.8 2.2 2.4 1.6 24.4 43.5 39.7 54.6 59.6 57.5 55.2 49.6 22.5 16.1 51.4 34.4 30.4 12.6
Standardized Precipitation Index -0.51 -1.35 -1.67 -2.02 -1.97 -2.15 -0.69 -0.16 -0.26 0.12 0.24 0.19 0.13 -0.01 -0.75 -0.99 0.04 -0.4 -0.51 -1.14