MONTHLY SUMMARY 



DECEMBER 1951 



Barometer, in inches 



(Readings reduced to sea level) 



Maximum 30.569, 20th 



Minimum 29.322, 15th 



Mean semi-daily 30.091 



Range 1.247 



Air Temperature, in degrees F. 



Highest 61, 8th 



Lowest —9, 20th, 28th 



Mean 29.8 



Range 70 



Highest mean daily 57.5, 8th 



Lowest mean daily 5, 17th 



Mean maximum 37.6 



Mean minimum 21.9 



Greatest daily range 34, 20th 



Least daily range 6, 6th 



Degree-days of heating load for 



month 1091.5 



Degree-days cumulative for season ..2419.5 



Precipitation, in inches 



Precipitation 4.35 



Snow 19.7 



Maximum precip. in 24 hrs 1.39, 21st 



Number of days with .01 or more 12 



Wind, in miles 



Total movement 3281 



Greatest daily movement 280, 10th 



Least daily movement 4, 1st 



Mean hourly velocity 4.4 



Maximum velocity 40, 15th 



Wind, direction 



Prevailing direction NW 



North, days 6 



Northeast, days 1 



East, days 



Southeast, days 6 



South, days 3 



Southwest, days 



West, days 5 



Northwest, days 10 



Weather 



Mean relative humidity, percent 84.0 



Mean cloudiness, percent 51.6 



Number of clear days 10 



Number of fair days 10 



Number of cloudy days 11 



Number of hours bright sunshine 136.8 



Percent of possible hours of 



bright sunshine 46.8 



Thunder and lightning 18th 



First snow 



Normal 



30 66 



29.27 



30,06 



1.38 



54.3 

 1.09 



27.5 

 56.2 



Extremes 



1162.5 

 2494.0 



3.39 

 8.50 



10 



4710 



6.3 

 31.4 



WNW 



69.4 

 54.9 



8 



9 



14 



128 



45.2 



Nov. 6 



31.104, 1949 

 28.85, 1915 



1.78, 1895, 1.01, 1892 



65.5, 1908 



—22.5, 1917 



36.9, 1891; 17.1, 1917 



i:n, 1901; .58, 1943 

 26.50, 1902, T, 1891, 1943 



17, 1902; 4, 1892, 1943 



6,694, 1925; 3,239, 1918 



66, 1949 



71, 1929; 39, 1919 



15, 1890, 0. 1948 



16. '09; 4, '89, '30, '31, 'Zd, '38 



25, 1948; 7, '09, 'ZZ 



172, 1896; 27, 1948 



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 tn 1950. 



