MONTHLY SUMMARY 



December, 1942 



Barometer, in inches 



(Readings reduced to sea level) 



Maximum 30.90, 27th 



Minimum _..._ 28.57, 2nd 



Mean semi-daily 30.027 



Range -____ 2.33 



Air Temperature, in degrees F. 



Highest _53, 2nd 



Lowest -IS, 20th, 21st 



Mean _ ..__._ 24.8 



Range 68 



Highest mean daily 37.5, 2nd 



Lowest mean daily -5, 20th 



Mean maximum „32.5 



Mean minimum ,,__..17.1 



Greatest daily range 42, 22nd 



Least daily range 4, 24th, 29th 



Precipitation, in inches 



Precipitation _. 6.03 



Snow - 7.00 



Maximum precipitation in 24 hrs. ._. 2.33, 30th 

 Number of days with .01 or more .10 



Wind, in miles 



Total movement 4967 



Greatest daily movement .__ 360, 31st 



Least daily movement 46, 25th 



Mean hourly velocity — 6.7 



Maximum velocity 48, 2nd 



Wind, direction 



Prevailing direction WNW 



North, days — 3 



Northeast, days ...0 



East, days 



Southeast, days ..4 



South, days 1 



Southwest, days : 1 



West, days 9 



Northwest, days .13 



Weather 



Mean relative humidity, percent ...71.7 



Mean cloudiness, percent 58 



Number of clear days 14 



Number of fair days 2 



Number of cloudy days ...15 



Number hours bright sunshine 135 



Percent of possible hours of bright 



sunshine 47.7 



Thunder and lightning 2nd 



Normal 



30.66 



29.27 



30.06 



1.38 



54.3 

 -1.9 

 27.5 

 56.2 



3.39 

 8.50 



10 

 4710 



31.4 



WNW 



69.4 



54.9 



8 



9 



14 



128 



45.2 



Extremes 



30.96, 1889 

 28.85, 1915 



1.78, 1895; 1.01, 1892 



65.5, 1908 



-22.5, 1917 



36.9, 1891; 17.1, 1917 



1j1, 1901 ; .87, 1896 

 26.50, '02; t, 1891 



17, 1902; 4, 1892 

 6,694, 1925; 3,239, 1918 



48, 1938 



71, 1929; '39, 1919 



15, 1890; 2, 1922, 1933 



16, '09 ; 4, '89 '30, '31, '36, '38 



23, '2>Z ; 7, '09, 'ZZ 



172, 1896; 63, 1933 



Note — The first column in the above summary gives observations made during 

 the month. The second column gives the averages based on observations made 

 from 1889 to 1938, except that humidity records are based on observations made 

 from 1929 to 1938. The third column gives extremes observed from 1889 to 1941. 



