Monthly Means and Extremes Period: 1971-2000
Pelton Dam, OR
Parameter Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Mean Temperature(F)
Maximum 46.1 53.0 61.7 69.5 78.3 86.5 95.4 95.1 86.1 72.3 54.3 46.0 70.4
Minimum 25.9 28.6 31.2 34.8 40.5 46.4 50.6 50.2 43.5 36.1 31.5 26.4 37.1
Mean 36.0 40.8 46.5 52.2 59.4 66.5 73.0 72.7 64.8 54.2 42.9 36.2 53.8
Extreme Temperature(F)
Maximum 71 78 86 95 108 108 114 117 108 103 81 68 114
Minimum -10 -11 10 17 24 29 36 36 25 14 -2 -15 -15
Precipitation(inches)
Monthly mean 1.65 1.10 .95 .80 .85 .56 .37 .44 .41 .65 1.53 1.49 10.80
Extreme 24 hr .93 1.10 .71 1.22 1.34 .75 .89 .72 1.15 .74 2.80 1.01 2.80
Snowfall(inches)
Monthly mean .90 .01 .00 .00 .00 .00 .00 .00 .00 .00 .68 1.06 2.16
Average number of days
Temperature
Maximum 90 or more .0 .0 .0 .6 4.0 10.1 21.5 21.5 10.6 1.1 .0 .0 68.5
Maximum 32 or less 3.3 .9 .0 .0 .0 .0 .0 .0 .0 .0 .6 2.7 7.5
Minimum 32 or less 23.8 19.2 18.8 11.7 4.1 .2 .0 .0 1.3 10.0 16.4 24.1 131.2
Minimum 0 or less .5 .4 .0 .0 .0 .0 .0 .0 .0 .0 .1 .5 1.6
Precipitation
.01 inches or more 9.9 9.8 8.6 6.6 6.0 4.2 2.6 2.7 3.5 5.1 10.4 10.1 78.5
.10 inches or more 5.3 3.5 3.3 2.5 3.0 1.8 1.4 1.4 1.4 2.2 4.3 4.7 34.4
.50 inches or more .6 .3 .2 .2 .2 .2 .2 .2 .1 .2 .6 .5 3.4
1.00 inches or more .0 .0 .0 .1 .1 .0 .0 .0 .0 .0 .1 .0 .4
Degree Days
Heating days @ 65 (F) 906 693 591 406 223 74 14 11 96 361 673 906 5021
Growing days @ 50 (F) 3 6 24 107 279 467 689 682 421 151 17 4 2819