MONTHLY SUMMARY 



January, 1947 



Barometer, in inches 



(.Readings reduced to sea level) 



Maximum ______ ___.-_ 30.89, 1st 



Minimum .__-__ _ -.29.19, 20th 



Mean semi-daily -__ - - 30.037 



Range ._____. , - _. 1 .70 



Air Temperature, in degrees F. 



Highest __,-_.. 55, 31st 



Lowest -___ -_ -1, 10th 



Mean 27.7 



Range _ 56 



Highest mean daily 44.5, 31st 



Lowest mean daily 12.5, 10th 



Mean maximum 36.2 



Mean minimum 19.2 



Greatest daily range . 32, 7th 



Least daily range 4, 3rd, 15th, 16th 



Precipitation, in inches 



Precipitation Z.2i7 



Snow _ . __ 3.0 



Maximum precip. in 24 hrs. .___ _-0.84, 20th 



Number of days with .01 or more 10 



Wind, in miles 



Total movement .__ 3874 



Greatest daily movement 332, 22nd 



Least daily movement __. 7, 15th 



Mean hourly velocity ___ 5.2 



Maximum velocity _ 32, 21st 



Wind, direction 



PrevaiHng direction NW 



North, days 10 



Northeast, days _.__ 



East, days ., 



Southeast, days ___ _— _ _____ 3 



South, days 3 



Southwest, days _ 



West, days , __ __ 5 



Northwest, days ___. 10 



Weather 



Mean relative humidity, percent _.71.3 



Mean cloudiness, percent , .56 



Number of clear days _ .7 



Number of fair days _ 9 



Number of cloudy days 15 



Number of hours bright sunshine 112 



Percent of possible hours of bright 



sunshine- _ 38.1 



Thunder and lightning — 



3.61 

 13.32 



11 



5055 



6.8 

 32.7 



WNW 



70.1 



55 



9 



9 



13 



137 



46.7 



7.15, 1898; 1.07, 1896 

 2>^, 1898, 1923; 1.50, '08 



15, '93, '20; 4, 1901 



7770. 1908; 2896, 1895 



47, 1938 



78, 1932; 2,7, 1908 



20, 1944; 2, 1914 



18,1890,1926:3, 1916, 1944 



22, 1923, 1931 : 4, 1920, 19.^0 



214, 1920; 74, 1932 



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. Tlie third column gives extremes observed from 1889 to 1946. 



