Standardized Precipitation Index Table

Western Climate Division

Massachusetts, Climate Division 01

Precipitation Data Table

Time Scale in Months (As of the end of Jul. 2026)
1 2 3 4 5 6 7 8 9 10 11 12 15 18 24 30 36 48 60 72
Accumulated Precipitation (in.) 7.68 10.47 13.49 16.58 21.16 22.36 24.73 28.12 30.86 35.86 39.13 41.69 56.43 67.39 84.23 109.9 141.87 197.42 247.45 299.89
Accumulated Precipitation Departure from Normal (in.) 3.21 1.78 0.73 -0.11 0.61 -1.27 -2.33 -2.84 -4.04 -2.94 -3.94 -5.7 -3.72 -3.64 -10.63 -8.58 -0.44 7.73 10.5 15.68
Accumulated Precipitation Percent of Average 172 121 106 99 103 95 91 91 88 92 91 88 94 95 89 93 100 104 104 106
Accumulated Precipitation Percentile (non-exceedance) 94.1 75.6 61.7 51.8 58.5 40 31.3 28.2 22.2 32 27.2 20.1 32.7 33.9 14.5 22.8 49.8 69.8 72.6 78.4
Standardized Precipitation Index 1.56 0.69 0.3 0.05 0.22 -0.25 -0.49 -0.58 -0.76 -0.47 -0.61 -0.84 -0.45 -0.41 -1.06 -0.74 0 0.52 0.6 0.78