9 
indications, and it may be assumed that the average for the entire 
region is not far from 20 inches. With this may be compared 26.32 
inches, the average annual precipitation for the middle of the State, 
and 34.33 inches for the eastern part. 
It is noteworthy that most of the precipitation on the plains is dur- 
ing the growing season. Dodge City, for instance, with only 19.84 
inches annually, has 15.5 inches in the six months from April 1 to 
October 1. Rochester, N. Y., with 35 inches annually, has but 17.5 
during the same period. In other words, 78 per cent of the precipita- 
tion at Dodge City comes at the time when it is most needed, while 
Rochester receives but 50 per cent of its total in the same time. 
One of the most disagreeable characteristics of the climate of the 
Plains is the high winds, which sweep across them unhindered by 
either natural or artificial barriers. The prevailing direction is north- 
west in winter and southerly in summer, and soil moisture is absorbed 
with extraordinary rapidity, especially in the warm season. The 
dreaded “ hot wind,” which strikes growing crops with such deadly 
effect, is a hot, dry blast of air that takes water from the leaf sur- 
faces of vegetation faster than it can be supplied by the roots; con- 
sequently plants wilt, and even die, if the wind is long continued. 
The northerly winter winds, while causing much less evaporation, 
are hard upon stock and trying for men. 
The average wind velocity at Dodge City, Kans., is 12 miles per 
hour. In spring, however, it 1s considerably higher, especially in the 
afternoon hours, when an average speed of 20 miles an hour may be 
maintained for a month at a time. High winds are also quite fre- 
quent. In the ten years ending with 1903 there were eighty-one 
occasions on which the wind blew at the rate of 40 miles and upward 
an hour. 
Asa result of these constant drying winds, taken in connection with 
other meteorological conditions which prevail in western Kansas, the 
annual evaporation from a water surface is about 54 inches. This 
means that if it were possible to have a lake in western Kansas whose 
level depended wholly upon direct precipitation and evaporation, its 
annual decrease in depth would be 34 inches. The relative humidity, 
according to the Dodge City record, averages 60 to 65 per cent. The 
following table is especially instructive: 
Annual precipitation and evaporation. 
| 
eee Excess of 
ree h Preeipi- | 2 vepO= 5 |x oe 
Station. | tation. | ration. | ore 
Inches. Inches. | Inches. 
eh SSD, ROS SEB ec OS Oy rea a oe 21. 94 55. 40 33. 46 
Pie Se (CHET - TGR ORG 2 See ae ee re Oe ne lee en eee cee 19. 84 | 54. 60 | 34. 76 
ENGIN bEMEaE RRO MING [) Dis 0s ek 2 2 ee Pe ee Su eb lucse dee 1 eee 18. 27 41.30 | 23. 038 
Si, WHRGSIN,, Mita: Bes 53 eo Se ee ge Sa ee ae ee aan epee eee 19. 50 22.10 2.60 
69616—Cir, 161—09 
2 
