Page:Handbook of Meteorology.djvu/250

 5 miles to 15 miles per hour. On sea and lake coasts it is materi- ally higher; and in a few mountain valleys it is lower than 3 miles.

Throughout the prairie region and the great plains, the wind is apt to be steady, its velocity varying but little during the daylight period. In regions where land breezes alternate with those from the sea, a short period of calm precedes each change.



The cooperative observation sub-stations, outnumbering the regular stations about twenty to one, are not equipped with recording instruments except as they are procured at private expense. For all observers—volunteer, regular and