Standardized Precipitation Index Table

Willamette Valley Climate Division

Oregon, Climate Division 02

Precipitation Data Table

Time Scale in Months (As of the end of Jan. 2026)
1 2 3 4 5 6 7 8 9 10 11 12 15 18 24 30 36 48 60 72
Accumulated Precipitation (in.) 3.46 14.73 20.51 25.57 26.82 27.29 27.32 28.35 30.02 32.28 41.44 49.16 75.62 81.58 103.74 141.91 161.99 214.23 265.96 316.48
Accumulated Precipitation Departure from Normal (in.) -5.04 -3.14 -6.09 -5.62 -6.55 -6.88 -7.42 -8.41 -9.86 -11.83 -9.06 -8.05 -8.25 -9.87 -10.76 -6.73 -9.71 -14.59 -20.05 -26.71
Accumulated Precipitation Percent of Average 41 82 77 82 80 80 79 77 75 73 82 86 90 89 91 95 94 94 93 92
Accumulated Precipitation Percentile (non-exceedance) 6.5 33.1 22.5 26.4 22.1 20.3 18.1 15.1 11.4 7.5 16.1 20.8 24.6 21.1 20.9 34.5 28.8 23 17.7 13.1
Standardized Precipitation Index -1.52 -0.44 -0.76 -0.63 -0.77 -0.83 -0.91 -1.03 -1.21 -1.44 -0.99 -0.81 -0.69 -0.8 -0.81 -0.4 -0.56 -0.74 -0.93 -1.12