422 Eighth Annual REroRT of the 



III. TEMPERATURE. 



The temperature oonditions which prevail in the vicinity of 

 New York, and the general influences to which they are due, 

 have already been referred to in section I. The local variations 

 •of temperature and their effects within the Stalte itself are shown 

 in deitail by the accompanying tables and charts, as regards both 

 average and extreme conditions, dates ol' frost, and periods of 

 navigation in lakes and rivers. 



In referring special features of temperature distribution (as 

 exhibited by the tables), to their proper causes, the effect of 

 altitude alone upon the normals of the variou'S stations should, in 

 the first place, be eliminated by reducing the temperatures at all 

 stations to sea-level. The results of such a reduction are shown 

 by means of isoithepmial lines drawn for the months of January 

 and July respectively, in diagrams 1 and 2. Foir reasons which 

 will appear further on, it has been assumed that the temperature 

 is lowered at the rate of 0.3 degrees F. per 100 feet of increased 

 altitude in January, and 0.4 degrees per 100 feet in July. The 

 rate of decrease is probably not perfectly constant for the entire 

 State, but must be assumed to be so foir purpo'ses of comparison. 



The first point to be considered is the variation of climate 

 which mayproperly be attributed to differences of latitude within 

 the State. The average temperature of the globe at the latitude 

 of New York's southern boundary (40 degrees 40 minutes north) 

 is for the yeair 55.6 *degrees; foir mid- winter (January) 3S.9 

 degrees, and for mid-summer (July) 72.5 degrees. Selecting the 

 normals of New York city and Malone as representing the actual 

 conditions which obtain at the northern and southern boundaries 

 of the State respectively, the following deviations from strictly 

 average conditions are shown: 



At New York city the temperature (reduced to sea-level) for 

 The 3'ea,r is 4.0° below the average of Lat. 40° 40'. 

 January is 9.0° below the average of Lat. 40° 40'. 

 July is 1.5° above the average of Lat. 40° 40'. 



• The values here giv«n were computed from the determination made by Ferrel, " Recent 

 Advances," p. 152. 



