CROP REGIONS OF OHIO 63 



of evaporation differs widely under various conditions. The 

 southern boundary of Ohio, along the river, is in approximately 

 the same latitude as Washington, D. C, while the northernmost 

 point approximates Cape Cod, Massachusetts, in latitude. The 

 summer temperature at these extremes would influence greatly 

 the evaporation rate. There is a difference of approximately a 

 thousand feet in elevation from the lowest part of the Erie Plain 

 to the highest point of the Allegheny Plateau. This would also 

 affect evaporation to a marked degree how, while the wind veloci- 

 ties would vary in the level regions and "cold waves pass across 

 the state with sufficient intensity to ventilate and invigorate the 

 towns and cities and send their health-giving winds into all parts 

 of the state, and yet the cold waves are not so severe in Ohio as in 

 corresponding latitudes in the Mississippi and Missouri valleys." 

 The fact of great significance is that Ohio lies directly across the 

 path of one of the main storm tracks, and there is rapid alter- 

 nation of areas of low and high barometric pressure. The writer 

 ('18 p. 55) has discussed the influence of this feature of climate 

 upon crops. 



The state is 205 miles long from north to south and the effect 

 of latitude is seen in the climatic difference in the northern and 

 southern extremes of Ohio. The influence of Lake Erie is to 

 counterbalance the effect of latitude in a narrow strip just south- 

 east of the lake. Lake Erie is an inland sea, giving an oceanic cli- 

 mate to a narrow strip of land bordering it. The work of Miller, 

 (1917), in Wisconsin shows the climatic effect of the lakes over 

 territory comparable to the Lake Erie region of Ohio. The 

 mean annual temperature in the northern part of the state is 

 48° F., in the central portion 51°, and in the southern portion 

 54° to 55° (Smith '12). The coolest sections of the state are in 

 the northeastern and northwestern districts, while the warmest 

 are in the extreme southern and southwestern counties. Isothermal 

 lines show the influence of elevation. From Champaign to Ottawa 

 counties, a distance of over 100 miles across the Erie Plain, the 

 average temperature varies less than one degree. The lowest mean 

 annual temperature is in Portage County, 47.2°. The highest, 

 55.5°, is in Scioto County. The precipitation shows similar dif- 

 ferences, increasing southward. The least precipitation is near 

 the western end of Lake Erie, and the greatest along the Ohio 

 River. 



