4 BULLETIN 402^ U. S. DEPARTMENT OP AGEICULTUEE. 



March, to July, inclusive. A more detailed discussion of climatic 

 data recorded at the Akron Field Station follows. 



/O 



PRECIPITATION. 



In general, the precipitation of eastern Colorado decreases as the 

 altitude increases, or from east to west. When the foothills are 

 reached, however, there is a rapid increase in rainfall. The rainfall 

 is also greater on the high divide between the Platte and Arkansas 

 Rivers than at lower elevations to the north or south. In the river 

 valleys the additional precipitation from local showers may con- 

 siderably affect the total. Local storms of greater or less importance 

 occur every year. They are most common during the summer 

 months. At other times the storm area is usually quite extensive. 

 The limits of the local storms are often very clearly marked. A 

 rainfall of an inch or more may occur at a distance of only 2 or 



3 miles from a point 

 where there is no pre- 

 cipitation. Torrential 

 rains are not uncom- 

 mon, and much dam- 

 age results from hail. 

 The distribution of 

 precipitation through- 

 out the year is usu- 

 ally favorable to ce- 

 real production. The 

 annual and seasonal 

 rainfall at Akron from 

 1905 to 1915 is shown 

 graphically in figure 2. 

 The annual and aver- 

 age precipitation by months for the 11 years from 1905 to 1915 is 

 given in Table I. The data for the first three years and portions of 

 the fourth and fifth years, as noted, are from the records of the United 

 States Weather Bureau. These observations were made at the town 

 of Akron, which is about 90 feet higher in elevation than the field 

 station and about 4 miles distant. The remaining data are from the 

 records of the Biophysical Laboratory of the Bureau of Plant Industry 

 at the Akron Field Station. 



The average precipitation in the 11-year period, 1905 to 1915, in- 

 clusive, as shown in Table I, is 19.72 inches. Of this total, 12.33 

 inches fell during the months from March to July, inclusive, or during 

 the period which most affects the production of the cereals. 



Fig. 2.— Diagram showing the seasonal and annual precipitation at 

 the Akron Field Station for eleven years, 1905 to 1915, inclusive. 

 The solid bars show the seasonal precipitation, while the total 

 length of the bars shows the annual precipitation. 



