Standardized Precipitation Index Table

Upper Southern Climate Division

Maryland, Climate Division 04

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.) 2.88 4.57 5.69 7.89 11.13 12.45 19.04 23.24 30.88 34.19 36.75 39.32 45.62 54.74 72.82 98.55 116.61 160.22 204.79 263.34
Accumulated Precipitation Departure from Normal (in.) -0.27 -1.91 -3.73 -4.74 -5.24 -8.34 -6.05 -5.72 -1.96 -2.09 -3.15 -3.41 -6.63 -8.92 -12.74 -8.04 -11.92 -11.24 -9.64 5.94
Accumulated Precipitation Percent of Average 91 71 60 62 68 60 76 80 94 94 92 92 87 86 85 92 91 93 96 102
Accumulated Precipitation Percentile (non-exceedance) 47.6 20.3 9 7.2 10.3 2.9 12 16 39.8 39.3 33.2 32.4 19.7 14.5 8.9 23 15.5 21.1 27.3 64.1
Standardized Precipitation Index -0.06 -0.83 -1.34 -1.46 -1.27 -1.89 -1.17 -0.99 -0.26 -0.27 -0.44 -0.46 -0.85 -1.06 -1.35 -0.74 -1.02 -0.8 -0.6 0.36