4 BULLETIN 211, U. S. DEPARTMENT OF AGRICULTURE. 
and June each year if there has been a normal rainfall the previous 4 
summer. But it is true of practically all of the State that May and 
June are the driest months of the year, and summer arrives without 
any heralding by spring. It has been said that there are but two 
seasons in the southern valleys, summer and late fall, and the longer 
of these issummer. The summer rains usually occur as rather violent 
local showers of short duration. The water falls from clouds that are 
high above the earth, and the air next the ground may be relatively - 
dry; in fact, it is not infrequent to see small, high clouds that are evi- — 
dently producing some rain, but the water evaporates at a lower level . 
and never reaches the ground. Drizzling rains from low-hung, drift- — 
ing clouds that roll along only a few hundred feet above the earth are - 
only occasional anywhere except upon the cloud-capped peaks of the | 
high mountains; and heavy general storms moving steadily over large 
areas are very rare. = | 
A study of the United States Weather Bureau reports indicates | 
that there are two factors fundamental in nature which determine ~ 
in a general way what the average precipitation of any point in — 
the State shall be. The first of these is the well-known relation 
between precipitation and altitude, depending upon the effect of 
forcing currents of moisture-laden warm air to higher atmospheric 
levels through the upward deflection of such currents by the moun- : 
tains. It thus happens that, other things being equal, the precipita- — 
tion increases with altitudinal i increase, though not always in a direct | 
ratio. 
The average Fea iaeun of any station in the State also seems — 
to be in some way dependent upon its distance from the southeast | 
_corner. If localities having the same altitude be considered, it 
appears that those in the southeastern corner have the greatest | 
average rainfall, and that this rainfall gradually diminishes as one | 
goes west and north. This fact would seem to suggest that the | 
source of the moisture lies to the southeast, possibly the Gulf of @ ; 
Mexico. Local factors enter into the case, sometimes decreasing, | 
sometimes augmenting the amount of precipitation for a particular 
location. Some of the extreme records for the State follow and will 
give an idea of the limits of variation. A normal rainfall chart for 
New Mexico has been published by the State immigration bureau. _ 
The maximum precipitation in the State recorded for any single 
calendar year is for Elk, 39.1 inches, in 1905. There is poet y 
some inaccuracy in this record, or the station is subjected to local — 
conditions which tend to increase the normal expectancy for this 
altitude, 7,400 feet. Cloudecroft (8,650 feet) received 32.32 inches 
highest record for Windsor (8,200 feet) is 27.92 inches in 1907. I 
lowest records occur in the lower valleys. San Marcial (4,439 feet) 
