MONTHLY SUMMARY 



September, 1947 



Barometer, in inches 



(Readings reduced to sea level) 



Maxi;T)um ..30.64, 18th 



Minimum . 29.62, 22nd 



Mean semi-dailv _.... 30.176 



Range ...' 1.02 



Air Temperature, in degrees F. 



Highest 89, 12th, 13th 



Lowest 29, 27th, 28th 



Mean 62.9 



Range 60 



Highest mean daily .79.5, 12th, 13th 



Lowest mean daily 43.5, ?7th 



Mean maximum ...74.9 



Mean minimum 50.9 



Greatest daily range ...37, 29th 



Least dailj' range 15, 14th 



Precipitation, in inches 



Precipitation 2.84 



Snow — 



Maximum precip. in 24 hrs. 1.21, 2nd 



Number of days with .01 or more ..7 



Wind, in miles 



Total movement .• ...3306 



Greatest daily movement 282, 30th 



Least daily movement 33, 5th 



Mean hourly velocity 4.6 



Maximum velocity 40, 29th 



Wind, direction 



Prevailing direction S 



North, days 4 



Northeast, days 1 



East, days 



Southeast, days 9 



South, days 9 



Southwest, days 1 



West, days 2 



Northwest, days 4 



Weather 



Mean relative humidity, percent 75.0 



Mean cloudiness, percent... 23.0 



Number of clear days 16 



Number of fair days 8 



Number of cloudy days 6 



Number of hours bright sunshine 249 



Percent of possible hours of 



bright sunshine 72.6 



Thunder and lightning 13th, 15th 



First frost 27th 



Normal 



30.45 

 29.57 

 30.06 



87.7 

 33.2 

 61.7 

 54.5 



4.24 

 10 



3271 



4.5 

 25.9 



WSW 



73.6 



49.9 



10 



10 



10 



201 



54.9 



Extremes 



30.65, 1924 

 28.41, 1938 



1.99, 1938; .57, 1910 



97, 1895, 1929 

 24.5, 1914 



14.55, 1938; .52, 1914 

 16, 1933; 3, 1903 



4,686, 1896; 1,414, 1894 

 80, 1938 



70, 1934; 27, 1908, 1914 

 19, 1932; 2, 1907, 1928 



19, 1908; 3, 1889 



20, 1934; 3, 1941 

 255, 1916; 106, 1934 



Sept. 21 Oct. 1.^. 1909, Aug. 22. 1894-95 



Note — The first column in the above summary 

 month. The second column gives the averages 

 1889 to 1938, except that humidity records are 

 1929 to 1938. The third column gives extremes 



gives observations made during the 

 based on observations made from 

 based on observations made from 



observed from 1889 to 1946. 



