MONTHLY SUMMARY 



July 1939 



Normal 



Extremes 



Barometer, in inches 



(Readings reduced to sea level) 



Maximum 30.28, 21st, 22nd 



Minimum 29.58, 14th 



Mean semi-daily 29.971 



Range 0.70 



Air Temperature, in degrees F. 



Highest 93, 7th, 8th 



Lowest 45, 3rd 



Mean 71.2 



Range 48 



Highest mean daily 81, 7th 



Lowest mean daily 60, 13th, 1 th 



Mean maximum 83 5 



Mean minimum . .58 8 



Greatest daily range 38, 4th 



Least daily range 12, 31st 



Precipitation, in inches 



Precipitation 2.30 



Snow 



Max. precipitation in 24 hrs 76, 14th 



Number of days with 01 or more 7 



Wind, in miles 



Total movement 3072 



Greatest daily movement 179, 2nd 



Least daily movement 48. 18th 



Mean hourly velocity 4.1 



Maximum velocity 25, 12th 



Wind, direction 



Prevailing direction WSW 



North, days 4 



Northeast, days 



East, days 1 



Southeast, days 7 



South, days 5 



Southwest, days 3 



West , days 3 



Northwest, days 8 



Weather 



Mean relative humidity, percent 65.1 



Mean cloudiness, percent 50 



Number of clear days 13 



Number of fair days 14 



Number of cloudy days 4 



Number hours bright sunshine 283 



Percent of possible hours of bright 



sunshine 61.3 



Thunder and lightning. . .7, 8, 14, 24, 25, 31 



30.27 



29.59 



29.96 



.68 



93.9 

 46.4 

 70.8 

 47.7 



4.10 



11 

 3422 



4.6 



28.7 



SW 



68.4 

 50.9 

 10 

 14 



7 

 268 



58 



30.50, 1892 

 29.27, 1932 



.97, 1892; .47, 1938 



104, 1911 

 40, 1890 ,1898 



14 51, 18)7; .70, 1929 



20, 1915;4, 1924 

 5,097, 1909; 1,109, 1894 



44, 1936 



69, 1914; 31, 1924 



22, 1923; 0, 1915 



24,'09,'21;5,'89,'23,'28,'36 



18, 1889; 0, 1910 



371, 1910; 180, 1931 



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 to 1938. 



