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 May 2025)
1 2 3 4 5 6 7 8 9 10 11 12 15 18 24 30 36 48 60 72
Accumulated Precipitation (in.) 3.37 8.27 23.63 35.9 40.2 59.59 76.9 88.69 92.03 95.11 96 100.83 122 168.98 198.45 259.82 289.14 420.06 527.53 630.89
Accumulated Precipitation Departure from Normal (in.) -1.35 -4.07 -0.32 -0.5 -12.45 -10.29 -9.26 -7.92 -9.41 -8.44 -9.21 -7.75 -10.53 -9.56 -18.77 -27.38 -36.81 -14.67 -15.68 -20.67
Accumulated Precipitation Percent of Average 71 67 99 99 76 85 89 92 91 92 91 93 92 95 91 90 89 97 97 97
Accumulated Precipitation Percentile (non-exceedance) 32.3 14.8 51.3 50.5 9.8 20.1 27 32.4 29.2 31.5 29.7 33.3 28.1 34.3 22.5 17.7 11.3 35 35.7 32.8
Standardized Precipitation Index -0.46 -1.04 0.03 0.01 -1.29 -0.84 -0.61 -0.46 -0.55 -0.48 -0.53 -0.43 -0.58 -0.4 -0.75 -0.93 -1.21 -0.38 -0.36 -0.45