MONTHLY SUMMARY 



SEPTEMBER, 1948 



Normal 



Extremes 



Barometer, in inches 

 (Readings reduced to sea level) 



Maximum 30.53. 17th 



Minimum 29.15, 29th 



Mean semi-daily 30.081 



Range 1.38 



Air Temperature, in degrees F. 



Highest 91, 11th 



Lowest 34, 17th 



Mean 63.7 



Range 57 



Highest mean daily 74.5, 6th 



Lowest mean daily 51.5, 22nd 



Mean maximum 78.1 



Mean minimum 49 



Greatest daily range 46, 11th 



Least daily range 12, 14th, 20th 



Degree-days of heating load for month 104 

 Degree — days cumulative for season 104 



Precipitation, in inclies 



Precipitation 1.91 



Snow 



Maximum precip. in 24 hrs 1.02, 9th 



Number of days with .01 or more 5 



Wind, direction I 



Prevailing direction SWj 



North, days 3 



Northeast, days 2 



East, days 2 



Southeast, days 5 



South, days 5 



Southwest, days 4 



West, days 2 



Northwest, days 7 



Weather 



Mean relative humidity, percent 69.8 



Mean cloudiness, percent 27.6 



Number of clear days 12 



Number of fair days 15 



Number of cloudy days 3 



Number of hours bright sun.ihine ...23 3 

 Percent of possible hours of 



blight sunshine 57.1 



Thunder and lightning 9th 



First frost 



30.45 

 29.57 

 30.00 



87.7 

 33.2 

 61.7 

 54.5 



4.24 



10 



Wind in miles ' 



Total movement 1731 3271 



Greatest daily movement 153, 24th 



Least daily movement 22, 29th 



Mean hourly velocity 2.6 4.5 



Maximum velocity 40, 18th 25.9 



WSW 



73.6 



49.9 



10 



10 



10 



201 



54.9 



— Sept. 21 



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; 23, 1947 



19. 1932; 2, 1907. 1928 



19, 1908; 3, 1889 



20. 1934; 3, 1941 

 255, 1916; 106. 1934 



Oct. 13, 1909 ; Aug." 22, 1894-95 



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

 during the month. The second column gives the averages based on observa- 

 tions 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 1947. 



