These statewide averages are obtained as follows: Each state is divided into climate divisions and an average precipitation value is calculated for each division. These division averages are then weighted by the amount of area within each division.
Source: National Climatic Data Center, Historical Climatography Series 4-2.
State Normals Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec | Annual
1931-60 1.57 1.31 1.17 .99 1.19 1.44 2.23 3.18 2.79 2.59 1.92 1.63 | 22.00
Alaska 1941-70 1.46 1.35 1.28 1.09 1.21 1.56 2.39 3.21 2.77 2.48 1.84 1.67 | 22.29
1951-80 1.37 1.31 1.19 1.11 1.18 1.65 2.34 3.00 2.73 2.51 1.89 1.67 | 21.94
1961-90 1.50 1.25 1.17 1.10 1.18 1.69 2.32 2.86 2.76 2.56 1.84 1.78 | 22.01
1971-00 1.63 1.29 1.20 1.04 1.21 1.67 2.23 2.88 2.88 2.59 1.99 1.89 | 22.50
1931-60 1.09 1.16 .93 .60 .29 .35 1.69 2.24 1.19 .87 .67 1.13 | 12.20
Arizona 1941-70 1.02 .83 .98 .57 .27 .30 1.75 2.16 1.08 .85 .70 1.17 | 11.69
1951-80 1.13 .92 1.09 .53 .34 .33 1.78 2.05 1.07 1.03 .81 1.12 | 12.20
1961-90 1.10 1.01 1.19 .54 .35 .29 1.86 2.07 1.34 1.06 .99 1.30 | 13.10
1971-00 1.30 1.25 1.35 .54 .42 .31 1.74 2.09 1.30 1.20 .96 1.12 | 13.59
1931-60 4.07 3.79 2.93 1.69 .84 .32 .12 .17 .34 1.21 2.04 3.95 | 21.47
California 1941-70 4.16 3.25 2.76 1.83 .78 .31 .13 .22 .30 1.22 2.77 3.87 | 21.61
1951-80 4.35 3.32 2.72 1.67 .70 .28 .17 .29 .47 1.11 2.62 3.58 | 21.27
1961-90 3.77 3.28 3.13 1.52 .61 .27 .18 .35 .58 1.25 3.14 3.35 | 21.43
1971-00 4.15 3.95 3.55 1.40 .83 .32 .19 .30 .58 1.20 2.62 3.10 | 22.18
1931-60 .83 .85 1.13 1.59 1.86 1.35 1.75 1.81 1.21 1.09 .74 .76 | 14.98
Colorado 1941-70 .82 .74 1.11 1.50 1.81 1.58 1.93 1.94 1.21 1.22 .78 .79 | 15.43
1951-80 .81 .72 1.07 1.32 1.81 1.36 1.90 1.83 1.21 1.09 .84 .83 | 14.78
1961-90 .72 .72 1.20 1.27 1.80 1.51 2.03 1.87 1.42 1.13 .93 .87 | 15.47
1971-00 .79 .75 1.29 1.47 1.92 1.44 2.01 1.95 1.35 1.20 .99 .76 | 15.93
Hawaii 1961-90 7.19 5.96 7.69 7.85 5.34 3.44 4.86 4.58 3.98 5.04 7.44 6.96 | 70.33
1971-00 6.64 5.06 7.15 6.39 4.27 3.59 4.79 4.27 4.05 4.73 6.92 5.85 | 63.70
1931-60 2.18 1.87 1.76 1.44 1.68 1.59 .60 .59 .92 1.58 1.94 2.33 | 18.47
Idaho 1941-70 2.32 1.75 1.59 1.49 1.84 1.91 .57 .79 1.02 1.54 2.11 2.34 | 19.26
1951-80 2.47 1.70 1.59 1.49 1.74 1.68 .66 .93 1.05 1.34 1.87 2.33 | 18.86
1961-90 2.22 1.68 1.69 1.50 1.77 1.64 .82 .96 1.19 1.29 2.07 2.19 | 19.02
1971-00 2.12 1.72 1.73 1.56 1.97 1.50 .92 .84 1.08 1.30 2.05 2.12 | 18.92
1931-60 .73 .66 .86 1.13 1.87 2.79 1.33 1.17 1.15 .99 .80 .77 | 14.25
Montana 1941-70 .83 .64 .79 1.24 2.09 3.01 1.37 1.26 1.29 .93 .86 .79 | 15.11
1951-80 .93 .68 .78 1.32 2.22 2.61 1.36 1.37 1.26 .96 .82 .85 | 15.16
1961-90 .88 .62 .88 1.27 2.36 2.43 1.46 1.38 1.44 .95 .82 .85 | 15.34
1971-00 .80 .60 .90 1.30 2.34 2.40 1.65 1.35 1.33 1.05 .85 .78 | 15.34
1931-60 .95 .89 .81 .79 .78 .53 .47 .40 .38 .68 .68 .90 | 8.25
Nevada 1941-70 .91 .80 .77 .78 .82 .76 .49 .51 .40 .60 .83 .93 | 8.59
1951-80 .94 .82 .81 .75 .87 .72 .53 .58 .53 .57 .74 .88 | 8.75
1961-90 .87 .84 .94 .78 .90 .73 .58 .72 .68 .67 .89 .86 | 9.46
1971-00 .96 .92 1.09 .76 1.01 .63 .51 .63 .71 .75 .81 .72 | 9.50
1931-60 .63 .60 .64 .69 1.14 1.04 2.13 2.28 1.59 1.12 .48 .64 | 12.99
New Mexico 1941-70 .56 .50 .64 .63 .93 1.03 2.28 2.37 1.49 1.11 .43 .68 | 12.65
1951-80 .57 .52 .61 .54 .89 .96 2.27 2.38 1.53 1.15 .56 .62 | 12.59
1961-90 .59 .60 .63 .57 .92 1.17 2.27 2.58 1.87 1.17 .73 .75 | 13.85
1971-00 .67 .60 .71 .63 1.11 1.23 2.27 2.64 1.82 1.34 .80 .76 | 14.58
1931-60 3.94 3.16 2.95 1.83 1.83 1.52 .43 .42 .99 2.41 3.44 4.20 | 27.12
Oregon 1941-70 4.24 2.98 2.74 1.81 1.91 1.52 .42 .60 .98 2.50 3.86 4.37 | 27.91
1951-80 4.40 2.95 2.90 1.87 1.73 1.27 .41 .76 1.08 2.15 3.70 4.47 | 27.70
1961-90 3.90 2.94 2.92 1.94 1.64 1.26 .52 .82 1.13 1.99 4.01 4.26 | 27.33
1971-00 3.79 3.16 2.93 2.18 1.88 1.27 .62 .73 1.07 1.90 3.89 3.97 | 27.38
1931-60 1.02 .99 1.06 .99 .92 .69 .81 1.01 .73 1.07 .84 1.03 | 11.17
Utah 1941-70 .96 .88 1.02 1.07 .91 .88 .75 1.10 .76 1.06 .92 1.06 | 11.37
1951-80 1.01 .92 1.01 1.02 .97 .68 .77 1.01 .83 .98 .90 .94 | 11.04
1961-90 .90 .89 1.15 1.07 1.04 .71 .91 1.06 1.07 1.12 1.00 .91 | 11.88
1971-00 1.05 .99 1.21 1.07 1.20 .64 .88 1.02 1.07 1.30 .97 .80 | 12.22
1931-60 5.28 4.17 3.78 2.41 1.97 1.94 .74 .86 1.76 3.72 5.18 6.11 | 37.92
Washington 1941-70 5.52 4.12 3.48 2.57 1.88 1.79 .74 1.04 1.78 3.74 5.34 5.86 | 37.98
1951-80 5.97 4.16 3.65 2.51 1.92 1.60 .79 1.24 1.81 3.25 5.19 6.34 | 38.41
1961-90 5.59 4.20 3.71 2.58 2.04 1.60 .91 1.16 1.78 3.06 5.54 5.97 | 38.14
1971-00 5.38 4.37 3.76 2.71 2.23 1.76 1.02 1.05 1.65 3.05 5.69 5.76 | 38.44
1931-60 .68 .66 .95 1.44 1.86 1.76 1.13 .96 .96 .93 .72 .65 | 12.71
Wyoming 1941-70 .67 .59 .85 1.37 1.90 2.10 1.05 .96 1.04 .90 .73 .66 | 12.83
1951-80 .68 .57 .79 1.32 1.92 1.74 1.10 1.02 .96 .86 .65 .64 | 12.25
1961-90 .63 .55 .82 1.33 1.94 1.71 1.24 1.01 1.17 .91 .73 .65 | 12.69
1971-00 .63 .57 .86 1.36 2.06 1.58 1.33 1.02 1.15 1.04 .74 .59 | 12.92