CLIMATOLOGY OF NEBRASKA. 25 



Mean Temperature of Summer. 



From the preceding tables it will be seen that the average mean 

 temperature of the summer months, that is of June, July and Aug- 

 ust, in Eastern Nebraska, is between 72 and 74 ; or, more accu- 

 rately, close to •,73°. At North Platte it averages slightly higher. 

 Now, the summer isotherm of 72 starts about one-third of the 

 distance north of the south line of New Jersey, runs northwest 

 till it strikes the Appalachians in Pennsylvania, then goes south 

 and west, appearing again a little south of the east edge of Ohio, 

 and from there keeps a westerly direction until it strikes the Mis- 

 souri near Sioux City. There it follows the Missouri around its 

 big bend in Northeastern Nebraska and into Dakota Territory, 

 until it reaches almost to the 46th parallel. From this last point 

 it again moves a little south of west, passing through a small cor- 

 ner of Northwestern Nebraska, and thence on to Fort Laramie, 

 and thence southward, mainly near to or along the foothills, until 

 the loftier regions of Mexico are reached. 



The summer isotherm of 76 is almost parallel with the last, 

 passing through Northern Kansas, but not reaching the State 

 line. Included between these two isotherms is a large part of 

 Southern New Jersey, Southern Pennsylvania, the southern half 

 of Ohio, and the greater part of Indiana and Illinois, the southern 

 half of Iowa, and the whole of Nebraska except a very small 

 patch in the northwestern corner of the State. Kentucky, Vir- 

 ginia, Maryland and Delaware are also necessarily included be- 

 tween these isotherms. Nebraska, therefore, has a mean summer 

 temperature considerably higher than States in the East in the 

 same latitudes. There are some advantages >in this high summer 

 temperature, particularly in fruit culture. It is well known, for 

 example, that some of the finest grapes only mature where the 

 summer temperature is from 68° to 72 . Our fine soils and nat- 

 ural drainage, therefore, would be without avail were it not that 

 these conditions are complemented by a high mean summer tem- 

 perature. 



The Mean Winter Temperature. 



The winter months are regarded as embracing December, Jan- 

 uary and February. The mean isochimal, or line of equal mean 

 temperature of 20 , according to the Smithsonian Reports, includes 

 the south half of the State, and the northeastern portion as far as 



