MARYLAND GEOLOGICAL SURVEY 



253 



Fahrenheit, or 3.5° less than the normal for Baltimore and vicinity. 

 The average annual temperature has varied from this figure between 

 the limits of 54.1° and 49.7°, the former value representing the ex- 

 tremely warm year of 1865 and the latter the exceptionally cold year 

 of 1875. The average temperature for the year considered in itself 

 affords but an inadequate idea of the true character of the conditions 

 of heat and cold of a given locality. The value 51.9° may be derived 



TABLE I. 



MEAN MONTHLY AND ANNUAL TEMPERATURE, 



WOODLAWN, CECIL COUNTY, MARYLAND FROM 1865 TO 1875. 



Latitude 39° 38' North ; Longitude 76° 4' West of Greenwich, Elevation 460 feet. 



Year. 



Jan. 



Feb. Mar. 



Apr. 



! 



May June 



July 



Aug. 



Sept. 



Oct. 



Nov. 



Dec. 



Ann'l 





1865 



1866 



1867 



1868 



1869.,.. 



1870 



1871 



1872. ... 



1873 



1874 



1875 



30.5 

 29.4 

 23.8 

 26.5 

 35.2 

 37.7 

 29.1 

 28.2 

 27.4 

 35.5 

 24.9 



32.4 

 32.8 

 38.2 

 24.1 

 35.4 

 31.6 

 31.1 

 30.1 

 28.8 

 32.9 

 23.1 



45.9 

 40.3 

 36.2 

 39.0 

 36.9 

 35.4 

 45.3 

 31.4 

 35.8 

 39.7 

 34.5 



54.8 

 54.0 

 52.4 

 45.6 

 51.6 

 50.9 

 55.8 

 52.0 

 48.6 

 42.8 

 45.4 



61.8 

 60.1 

 58.0 

 57.3 

 58.9 

 62.3 

 63.0 

 64.6 

 60.0 

 61.5 

 63.4 



73.5 

 70.7 

 70.7 

 69.6 

 70.8 

 72.4 

 71.2 

 73.4 

 71.2 

 73.6 

 71.3 



74.2 

 76.9 

 74.2 

 78.8 

 73.7 

 77.2 

 73.4 

 79.4 

 77.2 

 74.5 

 74.5 



71.6 

 69.2 



72.5 

 73.8 

 72.2 

 74.2 

 75.1 

 75.2 

 72.0 

 70.3 

 71.2 



70.6 

 66.7 

 66.3 

 65.5 

 65.6 

 65.9 

 60.1 

 67.3 

 65.3 

 66.5 

 63.4 



52.5 

 55.5 

 55.0 

 51.5 

 47.9 

 56.2 

 56.0 

 52.8 

 53.6 

 54.4 

 52.4 



44.7 

 46.1 

 45.2 

 43.3 

 38.0 

 43.5 

 39.7 

 38.6 

 36.8 

 42.0 

 39.5 



36.4 

 32.4 

 28.8 

 29.1 

 34.4 

 32.8 

 28.2 

 26.3 

 37.1 

 34.4 

 33.0 



54.1 

 52.8 

 51.8 

 50.3 

 51.7 

 53.3 

 52.3 

 51.6 

 51.2 

 52.3 

 49.7 



1865 

 1866 

 1867 

 1868 

 1869 

 1870 

 1871 

 1872 

 1873 

 1874 

 1875 



Average 



29.8 



31.0 



38.2 



50.4 



61.0 ; 71.7 



75.8 



72.5 



65.7 



53.4 



41.6 



32.1 



51.9 



Average. 



from mean monthly values which differ widely from one another, 

 representing a variable climate, or it may be composed of monthly 

 values approximately equal, representing an equable climate. In 

 Cecil county the average January temperature is 29.8° and the 

 average July temperature 75.8°, showing a difference of 45° between 

 the coldest and warmest months of the year when normal conditions 

 prevail. The difference becomes still greater when the coldest and 

 warmest months of extreme seasons are contrasted. For example, 

 February, 1875, was but 23.1°, while the average temperature of 

 July, 1872, was 79.4°, showing an extreme difference in monthly 



