180 THE CLIMATE OF CALVERT COUNTY 



The annual mean temperature of Calvert County is found to be 56.8°. 

 This mean is probably exceeded only at stations in St, Mary's County 

 and in the extreme southern counties of the Eastern Shore. Spring has 

 a temperature of 55°, summer 77°, autumn 59°, and winter 37°. 

 Autumn is 4° warmer than spring. The warmest month is July with a 

 mean temperature of 78°, and the coldest is January with a mean of 36°. 

 It will be of interest to compare these temperatures with similar data for 

 Garrett County, the coldest in Maryland : 



Annual 

 County Mean 



Garrett 47.0° 



Calvert 56.8° 



Garrett County is much colder chiefly on account of its far greater ele- 

 vation above sea level. The temperature rises most rapidly from April 

 to May (difference in means 10°) and as the sun declines after reaching 

 its highest point a comparatively slow fall in temperature occurs until 

 after the autumnal equinox when it becomes very rapid, so that the 

 difference between the September and October means is over 12°. 



The extremes in Calvert County are, maximum 103°, minimum 5° 

 below zero, both at Solomons. The maximum is the highest temperature 

 recorded in the county, but at Charlotte Hall a minimum of 19° below 

 zero occurred in February, 1899, and it is probable that similar low 

 temperatures were felt in the northern portion of Calvert County. Both 

 of these extremes have been exceeded in other counties of Maryland. The 

 highest temperature officially recorded for the State is 109°, July 3, 



1898, at Boettcherville, near Cumberland, Allegany County. The lowest 

 temperature ever recorded in Maryland was 26° below zero February 10, 



1899, at Sunnyside in Garrett County. The monthly mean temperature 

 has exceeded 80° on rare occasions at stations in Calvert and neighboring 

 counties. The highest mean was 82.7° at Solomons, August, 1900. The 

 lowest monthly mean was 24.6° at Jewell in January, 1893. This gives 

 a possible range in monthly mean temperatures of 58°, a fact which suffi- 

 ciently emphasizes the continental character of the climate of this 

 region. 



