Standardized Precipitation Index Table

East Slope Cascades Climate Division

Washington, Climate Division 06

Precipitation Data Table

Time Scale in Months (As of the end of Sep. 2020)
1 2 3 4 5 6 7 8 9 10 11 12 15 18 24 30 36 48 60 72
Accumulated Precipitation (in.) 1.97 2.3 2.45 3.94 6.19 7.21 9.19 13.77 22.68 27.69 29.15 32.1 36.94 43.09 66.05 73.21 103.63 146.69 192.09 225.11
Accumulated Precipitation Departure from Normal (in.) 0.54 0.09 -0.41 -0.42 0.07 -1.04 -2.67 -2.46 0.59 -0.63 -4.94 -4.92 -2.94 -2.19 -8.05 -9.13 -7.51 -1.48 6.95 3.09
Accumulated Precipitation Percent of Average 138 104 86 90 101 87 78 85 103 98 86 87 93 95 89 89 93 99 104 101
Accumulated Precipitation Percentile (non-exceedance) 76.2 60.3 42.6 44.1 55.7 34.2 16.2 25.2 58 47.5 21.5 23.6 34.6 39.4 18.9 16.9 26.5 46.9 68.3 58.3
Standardized Precipitation Index 0.71 0.26 -0.19 -0.15 0.14 -0.41 -0.99 -0.67 0.2 -0.06 -0.79 -0.72 -0.4 -0.27 -0.88 -0.96 -0.63 -0.08 0.47 0.21