Monthly Summary 



Apiil, 1931 



Normal 



Extremes 



Barometer 



(Readings reduced to sea level) 



Maximum 30.51> 12th 



Minimum 29.30, 1st 



Mean semi-daily 30.008 



Range 1.21 



Air Temperature 



Highest 79, 20th, 21st 



Lowest 27,25th 



Mean 46.7 



Monthly range 52 



Highest mean daily 59, 22nd 



Lowest mean daily 36, 1st 



Mean maximum 68.7 



Mean minimum 35.3 



Greatest daily range 42, 20th, 21st 



Least daily range 7, 7th 



Precipitation 



Precipitation. In inches 2.95 



Snow, in inches 2.00 



Maximum precipitation in 24 hrs. .96 



26th 

 Number of days on which .01 or 



more inches of rain fell 11 



Wind (miles) 



Total movement 5,674 



Greatest daily movement .... 391, 27th 



Least daily movement 64, 9th 



Mean hourly velocity 8 



Maximum velocity for 5 min 39,29th 



Wind (direction) 



Prevailing direction wnw 



North, days 6 



Northeast, days 1 



East, days 



Southeast, days 6 



South, days 4 



Southwest, days 1 



West, days 5 



Norttawest, days 7 



Weather 



Mean relative humidity, per cent. . 55.0 



Mean cloudiness, per cent 53 



Number of clear days 13 



Number of fair days 7 



Number of cloudy days 10 



Number of hours bright sunshine 219.7 

 Percent of possible hours of bright 



sunshine 55.0 



Frosts after the 15th: 16th, 17th, 19th, 



24th, 25th, 30th. 



30.48 



29.41 



29.99 



1.08 



79.5 

 21.6 



45.8 

 57.8 



3.27 

 2.32 



11 



5,436 



7.5 

 29 



69.6 

 49.2 

 11 

 10 

 9 

 221 



55.0 



30.71, 1911 

 29.07, 1930 



1.52, 1930; 0.72, 1919 



88.5, 1896 

 8.5, 1923 



6.89, 1929; 0.76, 1892 

 11, 1891; 0,1910 



18, 1909; 3, 1892 

 ?,208, 1908; 3,853, 1917 



39, 1916 



81.2, 1916; 54.5, 1892 



75, 1901 ; 34, 1925, 1927 



19, 1911; 3, 1898, 1902 



18, 1915; 2, 1894, 1901 



22, 1901; 3, 1899, 1924 



296, 1911; 103, 1901 



Note— The first coIuqjii in the above summary irives observations made durinu' the 

 month. The second column gives averages based on observations made from l!?«'j to 

 ty2b. The third column aivea extremes observed from 18S'.) to lOaO. 



