MONTHLY SUMMARY 



September, 1941 



Normal 



Extremes 



Barometer, in inches 



(Readings reduced to sea level) 



Maximum 30.43, 20th 



Minimum 29.58, 6ih 



Mean ,semi-daily 30.087 



Range 0.85 



Air Temperature, in degrees F. 



Highest 91, 10th, 16th 



Lowest 28, 30th 



Mean 62.5 



Range 63 



Highest mean daily 78 5, lOi h 



Lowest mean daily 44, 30th 



Mean maximum 77.0 



Mean minimum 48.0 



Greatest daily range 40, 23rd 



Least daily range 18, 1 Itli 



Precipitation, in inches 



Precipitation 2 88 



Maximum precipitation in 24 hrs. 2.04, 1st 



Number of days with .01 or more 5 



Wind, in miles 



Total movement 3945 



Greatest daily movement 252, 7th 



Least daily movement 54, 27tl 



Mean hourly velocity 5.5 



Maximum velocity 28, 1st, 7th, 1 Ith 



Wind, direction 



Prevailing direction W 



North, days .4 



Northeast, days 



East, days 



Southeast, days 2 



South, day.s 10 



Southwest, days 3 



West, days 



Northwest, days 11 



Weather 



Mean relative humidity, percent 67.0 



Mean cloudiness, percent 36.0 



Number of clear days 23 



Number of fair days 4 



Number of cloudy days 3 



Number hours bright .sun.shine 307 



P.Tcent of possible hours of bright 



sunshine 82.3 



Thunder and lightning 1st, 10th 



First frost Sept 30 



30.45 

 29.57 

 30.06 



87.7 

 33.2 

 61.7 

 .'•)4.5 



4.26 



10 



3271 



4.5 

 25.9 



WSW 



73 6 



49.9 



10 



10 



10 



201 



54.9 



ept. 21 



30.65, 1924 

 28.41, 1938 



1.99, 1938; .57, 1910 



97, 1895, 1929 

 24.5, 1914 



14..^5, 1938; .52, 1914 



10, 1933; 3, 1903 



4,086, 1896; 1,414, 1894 



SO, 1938 



70, 1934; 27, 1908, 1914 



19, 1932; 2, 1907, 1928 



19, 1908; 3, 1889 



20, 1934; 4, 1908, 1916 

 255, 1916; 106, 1934 



Aug. 22, '94, '95; Oct. 13, '09 



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 tliat humidity records are based on observations made from 

 1929 to 1938. The third column gives extremes observed from 1889 to 1940. 



