Standardized Precipitation Index Table

Southwestern Climate Division

Montana, Climate Division 02

Precipitation Data Table

Time Scale in Months (As of the end of Jul. 2020)
1 2 3 4 5 6 7 8 9 10 11 12 15 18 24 30 36 48 60 72
Accumulated Precipitation (in.) 1.07 5.16 7.01 8.26 9.96 12.01 13.45 14.59 15.48 17.27 19.87 20.92 26.96 33.93 41.32 56.18 66.51 89.34 109.71 131.44
Accumulated Precipitation Departure from Normal (in.) -0.34 1.04 0.13 -0.64 -0.82 -0.22 -0.43 -1.01 -1.78 -1.52 -0.55 -0.8 -1.64 -0.03 -2.15 0.48 1.31 2.46 1.15 1.17
Accumulated Precipitation Percent of Average 76 125 102 93 92 98 97 94 90 92 97 96 94 100 95 101 102 103 101 101
Accumulated Precipitation Percentile (non-exceedance) 38.7 76.4 56.5 40.8 38.2 48.4 45 36.4 27.4 31 44.7 41 34.4 51.2 32.7 54.9 60 64.6 56.6 56
Standardized Precipitation Index -0.29 0.72 0.16 -0.23 -0.3 -0.04 -0.13 -0.35 -0.6 -0.5 -0.13 -0.23 -0.4 0.03 -0.45 0.12 0.25 0.37 0.17 0.15