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 Mar. 2024)
1 2 3 4 5 6 7 8 9 10 11 12 15 18 24 30 36 48 60 72
Accumulated Precipitation (in.) 2.81 6.06 12.46 18.58 22.98 24.78 26.57 27.26 27.55 28.4 29.47 32.11 41.8 56.14 67.28 95.92 100.92 137.07 172.92 203.04
Accumulated Precipitation Departure from Normal (in.) -0.75 -1.86 -1.31 -1.4 -2.78 -3.91 -3.55 -3.63 -3.98 -4.63 -5.32 -4.82 -8.91 -9.55 -6.66 -6.73 -9.96 -10.76 -11.89 -18.73
Accumulated Precipitation Percent of Average 79 77 90 93 89 86 88 88 87 86 85 87 82 85 91 93 91 93 94 92
Accumulated Precipitation Percentile (non-exceedance) 36.9 26.5 39.4 41.4 34.1 28.4 30.8 30.1 28.1 24.4 21.6 24.2 11.9 13.8 24.5 28.2 19.8 21.9 22.4 13.2
Standardized Precipitation Index -0.33 -0.63 -0.27 -0.22 -0.41 -0.57 -0.5 -0.52 -0.58 -0.69 -0.78 -0.7 -1.18 -1.09 -0.69 -0.58 -0.85 -0.78 -0.76 -1.12