Standardized Precipitation Index Table

Cascade Mountains West Climate Division

Washington, Climate Division 05

Precipitation Data Table

Time Scale in Months (As of the end of Jun. 2020)
1 2 3 4 5 6 7 8 9 10 11 12 15 18 24 30 36 48 60 72
Accumulated Precipitation (in.) 4.18 9.56 12.71 19.15 32.07 55.37 67.88 71.94 80.44 87 88.53 90.08 102.87 122.02 160.38 207.88 251.71 359.23 463.53 547.36
Accumulated Precipitation Departure from Normal (in.) 0.96 2.25 -0.4 -3.04 0.05 10.2 9.03 -0.08 0.59 3.2 2.98 3.13 2.81 -10.02 -13.52 -11.21 -9.19 11.38 28.92 26.21
Accumulated Precipitation Percent of Average 130 131 97 86 100 123 115 100 101 104 103 104 103 92 92 95 96 103 107 105
Accumulated Precipitation Percentile (non-exceedance) 75.4 83.7 48.5 29.8 53.1 87.9 81.3 52 54 61.3 60.6 61 59.7 28.3 25.3 32.2 36.8 65.7 80.5 76.4
Standardized Precipitation Index 0.69 0.98 -0.04 -0.53 0.08 1.17 0.89 0.05 0.1 0.29 0.27 0.28 0.24 -0.57 -0.67 -0.46 -0.34 0.4 0.86 0.72