Standardized Precipitation Index Table

West Olympic Coastal Climate Division

Washington, Climate Division 01

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.) 10.27 19.85 38.39 55.92 69.3 77.12 82.45 83.35 84.53 85.43 86.57 98.64 129.44 168.74 196.53 292.93 312.51 423.75 527.06 621.81
Accumulated Precipitation Departure from Normal (in.) -1.31 -4.17 -1.98 -1.71 -4.6 -7.22 -6.74 -7.93 -8.42 -10.88 -14.47 -10.05 -19.64 -24.35 -20.93 -8.96 -13.73 -11.15 -16.4 -30.08
Accumulated Precipitation Percent of Average 89 83 95 97 94 91 92 91 91 89 86 91 87 87 90 97 96 97 97 95
Accumulated Precipitation Percentile (non-exceedance) 44.6 30.6 45.2 47.3 39.8 34.6 36 33.2 32.1 26.7 19.5 28.5 16.6 14.9 20.3 39.4 34 39.1 35.4 26
Standardized Precipitation Index -0.13 -0.51 -0.12 -0.07 -0.26 -0.39 -0.36 -0.43 -0.47 -0.62 -0.86 -0.57 -0.97 -1.04 -0.83 -0.27 -0.41 -0.28 -0.37 -0.64