8 
The Colorado Experiment Station 
TABLE I.—DECREASE IN TEMPERATURE WITH INCREASE IN ALTITUDE. 
Altitude Decrease of temperature per 1000 feet elevation (1915) 
Station in Monthly and yearly means 
Feet. 
Jan. 
Feb. 
Mar. 
Apr. 
Salida . 
Leadville . 
7035 
10248 
2.5 
3.3 
3.9 
3.2 
Denver . 
Idaho Springs.. 
5272 
7543 
1.4 
2.2 
1.4 
3.0 
Ft. Collins. 
Long’s Pk. . . . 
4985 
8600 
1.4 
1.9 
2.2 
3.2 
(near) 
Colo. Springs... 
Lake Moraine. . 
6098 
10265 
1.8 
2.5 
3.2 
3.4 
Glenwood Spgs. 
Aspen . 
5758 
7981 
—.03 
3.2 
5.3 
5.0 
Durango . 
Silverton . 
6546 
9400 
2.3 
3.4 
4.1 
2.9 
Glenwood Spgs. 
Marble . 
5758 
7951 
-.03 
2.0 
3.4 
2.7 
Garnett . 
Wagon Wh Gap 
7576 
9610 
1.6 
3.8 
5.2 
4.0 
Delta . 
Cedaredge . . .. 
5025 
6175- 
—3.4 
0.04 
2.8 
3.3 
Boulder . 
Frances . 
5347 
9300 
2.5 
2.6 
2.0 
3.1 
Average. 
.98 
2.5 
3.4 
3.4 
May June July Aug. Sep. Oct. Nov. Dec. Year 
3.5 
3.4 
3.1 
2.3 
2.3 
2.9 
4.3 
3.3 
3.2 
3.3 
2.9 
2.9 
3.3 
3.2 
2.9 
3.2 
2.2 
2.7 
3.1 
3.3 
3.0 
3.0 
2.6 
1.9 
2.1 
1.1 
2.6 
3.3 
2.3 
2.7 
2.8 
2.9 
2.5 
2.8 
2.4 
2.6 
4.1 
3.2 
2.5 
3.1 
3.2 
2.7 
3.1 
3.1 
3.2 
4.2 
5.2 
2.2 
4.2 
3.5 
3.1 
2.9 
0.9 
3.5 
2.3 
2.1 
1.7 
1.8 
2.1 
2.0 
1.7 
1.0 
0.8 
4.8 
3.9 
2.6 
3.2 
3.4 
2.7 
2.8 
1.6 
3.3 
3.2 
4.6 
4.5 
• • 
2.0 
—.01 
2.1 
0.04 
• • 
3.5 
3.8 
2.9 
2.7 
2.7 
2.6 
3.4 
2.0 
2.8 
3.5 
3.5 
2.8 
2.9 
2.8 
2.3 
2.8 
1.8 
2.7 
The difference between low and high altitude stations in the 
mean temperatures for January is less than for any other month. 
In fact, the records show that the mean temperature for January, 
1915, at Marble (7,951 feet) is .6° higher than that at Glenwood 
Springs (5,758 feet), and that at Cedaredge (6,175 feet) the mean 
temperature for January of that year was 3.9° higher than at Delta 
(5,025 feet). In general, the differences in temperature between 
low and high altitude stations are less during the winter months 
than during the summer months, as may be seen from Table I. As 
a general rule, it may be stated that in Colorado an increase in 
elevation of 1,000 feet decreases the mean temperature for the year 
about 2j^ 0 ; for the summer months (June, July, August), about 
3°; for the fall, about 2J^°; winter, about 1 J4°; and spring, about 
3j4°. That is, in order to effect a decrease of 1° in the mean tem¬ 
perature for the year, one must ascend about 370 feet; to effect a 
decrease in the mean temperature for the spring, about 294 feet; 
summer, about 322 feet; fall, about 361 feet; and for the winter, 
about 588 feet. There is a retardation in the development of the 
vegetation, amounting to about 13 days for every 1,000 feet in¬ 
crease in altitude. 
