MONTHLY SUMMARY 



April 1940 



Barometer, in inches 



(Readings reduced to sea level) 



Maximum 30.38, 29th 



Minimum 29.40, 22nd 



Mean semi-daily 29.951 



Range 0.98 



Air Temperature, in degrees F. 



Highest 74,30th 



Lowest 20, 14th 



Mean 42.1 



Range 54 



Highest mean daily 56.5 



Lowest mean daily 28.5, 13th 



Mean maximum 51.6 



Mean minimum 32.6 



Greatest daily range 40, 29th 



Least daily range 5, 20th 



Precipitation, in inches 



Precipitation 6.37 



Snow 6.50 



Maximum precipitation in 24 hrs. 



1.66, 12th, 13th 



Number of days with .01 or more 14 



Wind, in miles 



Total movement 5497 



Greatest daily movement 390, 1st 



Least daily movement 78, 18th 



Mean hourly velocity 7.6 



Maximum velocity 40, 6th 



Wind, direction 



Prevailing direction NNW 



North, days 



Northeast, days 



East, days 2 



Southeast, days 3 



South, days 



Soutliwe.st, days 



West, days 



Northwest, days 10 



Weather 



Mean relative humidity, percent 67.3 



Mean cloudiness, percent 52 



Number of clear days 13 



Number of fair days 7 



Number of cloudy days 10 



Number hours bright sunshine 207 



Percent of possible hours of bright 



sunshine 51.5 



Thunder and lightning 



Last snow Apr. 22 



Normal 



30.48 



29.38 



29.99 



1.11 



79.4 

 22.0 

 45.7 

 57.4 



56.8 

 34.8 



3.35 



2.17 



11 

 5404 



7.5 

 31.4 



WNW 



61.6 



51.8 



11 



9 



10 



220 



54.7 



Apr. 15 



Extremes 



30.71, 1911 

 28.99, 1907, 1929 



1.52, 1930; .72, 1919 



88.5, 1896 



8.5, 1923 



52, 1921; 41.2, 1926 



6.89, 1929; .76, 1892 

 11, 1891; 0, 1910, 1934 



18, 1909, 3, 1892 

 8208, 1908; 3853, 1917 



40, 1935, 1938 



75, 1901; 34, 1925, 1927 



19, 1911; 3, 1898, 1902 



18, 1915; 2, 1894, 1901 



22, 1901; 3, 1899, 1924 



296, 1911; 103, 1901 



Mar. 14, 1910; May 11, 1907 



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 1939. 



