CLIMATIC INFLUENCES OF BODIES OF WATER 143 



159. Effects of Lake Michigan on temperature. In the pre- 

 ceding discussion of the lake breeze we have noted that the 

 effects of this breeze are restricted to a narrow area near 

 the shore. The effects of the lakes are carried much farther 

 inland, however, by other means. We need to study again 

 the table of mean monthly temperatures in order to see what 

 this effect is. Since the three points are in the same latitude 



FIG. 77. Temperatures during a cold wave 



The diagram represents the variation in temperatures between three cities on the 



dates January 2 to January 15, 1912. Grand Haven is in the latitude of Madison, 



but its temperature is like that of St. Louis 



(fig. 76) and are so located that one is close to the east shore 

 of the lake, one near the west shore, and one remote from the 

 lake, we shall have proper points for comparison. 



If we give our attention to the summer months, we find 

 that the means are a little lower at Grand Haven than at Mil- 

 waukee, and highest of the three at Madison. From this it 

 .appears that, in the case of these three towns at least, the lake 



