MONTHLY SUMMARY 



Mav 1939 



Normal 



Extremes 



Barometer, in inches 



(Readings reduced to sea level) 



Maximum 30.30, 13th 



Minimum 29.43, 9th 



Mean semi-daily 29.960 



Range 0.87 



Air Temperature, in degrees F. 



Highest 89, 7th, 28th, 31st 



Lowest ; 32, 14th, 16th 



Mean 59.7 



Range , 57 



Highest mean daily 77, 28th 



Lowest mean daily 46, 13th 



Mean maximum 72.2 



Mean minimum 47.2 



Greatest daily range 45, 19th 



Least daily range 6, 22nd 



Precipitation, in inches 



Precipitation 2.15 



Snow 



Max. precipitation in 24 hrs 1.40, 28th 



Number of days with .01 or more 4 



Wind, in miles 



Total movement 4007 



Greatest daily movement 220, 4th 



Least daily movement 64. 23rd 



Mean hourly velocity 5.4 



Maximum velocity 39, 28th 



Wind, direction 



Prevailing direction WNW 



North, days 7 



Northeast, days 1 



East , days 



Southeast, days 



South, days 2 



Southwest, days 4 



West , days 3 



Northwest, days 7 



Weather 



Mean relative humidity, percent 60 5 



Mean cloudiness, percent 55.2 



Number of clear days 13 



Number of fair days 12 



Number of cloudy days 6 



Number hours bright sunshine 284 



Percent of possible hours of bright 



sunshine 62.7 



Thunder and lightning 9th, 21st, 28th 



Last frost . . Mav 16 



30.39 

 29.51 

 29.96 



86.1 

 31.2 

 57.1 

 54.9 



3.60 



12 

 4504 



6.1 



28.8 



W 



60.7 



52.1 



11 



11 



9 



252 



55.6 



Mav 12 



30.62, 

 29.10, 



94.5, 1896, 

 24.0, 



1936 

 1938 



1911 

 1900 



7.44, 1931; .48, 1903 



20, 1901; 5, 

 5946, 1907; 2180, 



1903 

 1894 



45, 1935 



70, 1901; 30, 



20, 1923; 0, 



17, 1907, 1926; 5, 



20, 1927; 3, 1903, 



334, 1922; 137, 



1923 

 1927 

 1923 

 1922 

 1927 



June 8.1932; Apr. 23, 1904 



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. 



