MONTHLY SUMMARY 



May, 1931 



Normal 



Barometer 



(Reading's reduced to sea level) 



Maximum 30.21, 4th, 27th 



Mmimum 29.55, 16th 



Mean semi-daily 29.934 



Range 66 



Air Temperature 



Highest 91,29th 



Lowest 30, 1st, 4th 



Mean 58.1 



Monthly range 61 



Highest mean daily 73.5, 30th 



Lowest mean daily 43.5, 1st 



Mean maximum 70.0 



Mean minimum 46.2 



Greatest daily range 42, 6th 



Least daily range 4, 14th 



Precipitation 



Precipitation. In inches 7.44 



Snow, in inches 



Maximum precipitation in 24 hrs. 2.57, 



23rd 

 Number of days on which .01 or 



more inches of rain fell 16 



Wind (miles) 



Total movement 4,154 



Greatest daily movement .... 262, 3rd 



Least daily movement 57, 28th 



Mean hourly velocity 5.6 



Maximum velocity for 5 min 28, 3rd 



(foriected to conform to H cuj) anemometer) 

 Wind (direction) 



Prevailing direction s 



North, days 4 



Northeast, days 



East, days 



Southeast, days 12 



South, days 3 



Southwest, days 4 



West, days 3 



Northwest, days 5 



Weather 



Mean relative humidity, per cent. . 63 



Mean cloudiness, per cent 66 



Number of clear days 11 



Nuinber of fair days 7 



Number of cloudy days 13 



Number of hours bright sunshine 200.9 

 Percent of possible hours of bright 



sunshine 44.0 



Thunder and lightning 10th, 23rd, 31st 



Frosts 1st, 4th 



Last frost 



30.38 

 29.51 

 29.95 



.88 



85.5 

 30.8 

 56.8 

 54.6 



Extremes 



3.63 



12 



4,540 



6.1 

 25 



70.7 

 51.5 

 10 

 11 

 10 

 250.1 



55.2 



12th 



30.55, 1895 

 29.16, 1893 



1.16, 1893; 0.60, 1899 



94.5, 1911 

 24.0, 1900 



6.91, 1901; 0.48, 1903 



20, 1901; 5, 1903 



5,946, 1907; 2,180, 1894 



35, 1912 



83.9, 1927; 59.3, 1891 



70, 1901 ; 30, 1923 



20, 1923; 0, 1927 



17, 1907, 1926; 5, 1923 



20, 1927; S, 1903, 1922 



334, 1922; 137, 1927 



J'e 3, 1908; Apr. 23, 1904 



Note— The first column in ttie above summary gives observations made during- tlie 

 month. The second column gives averages based on observations made from 1889 to 

 r.)28. Tlie third column gives extremes observed from 18811 to VXM). 



