RAINFALL. 



265 



Puget Sound region, and even there the excess over the Hatteras 

 figure is not great. Moreover, this humiditj^ is distributed throughout 

 the months of the year with remarkable uniformity, the variation 

 between any two months amounting to not more than o per cent. 



PRECIPITATION. 



This is stated in centimeters and inclies. Annual, 159.4 centimeters 

 {66.41 inches), as compared with 125.6 centimeters (52.34 inches) at 

 Cape Henrj^, 125.0 centimeters (52.1 inches) at Norfolk, and 130.4 

 centimeters (54.34 inches) at Wilmington. Monthlj^, as follows: 



Month. 



January. 

 February 

 March . . . 

 April 



Cen- 

 time- 

 ters. 



14.3 

 10.7 

 14.6 

 11.3 



Inch 

 es. 



5.91 

 4.47 

 6.10 

 4.73 



Month. 



May ... 

 June... 

 July... 

 August 



Cen- 

 time- 

 ters. 



11.0 

 10.9 

 15.4 

 15.3 



Inch- 

 es. 



4.60 

 4.57 

 6.43 

 6.a5 



Month. 



September 

 October . . . 

 November 

 December . 



Cen- 

 time- 

 ters. 



Inch- 



15. 4 

 14.8 

 13.4 

 13.1 



ti.44 

 6.17 

 5.18 

 5.47 



The average annual number of rainy days is 123.8, as compared 

 with 125 at Cape Henry, 131.3 at Norfolk, and 128.8 at Wilmington. 

 The average monthl}^ number of raiu}^ days is as follows : 



At Hatteras the precipitation consists almost entirely of rain. Rain- 

 bearing storms usually approach from a westerl}' direction. AVinter and 

 spring rains are usuallj^ of light intensity and long duration, while 

 those of the summer and fall are more often brief and torrential in 

 character. 



The results viewed comparatively are as follows: Tlie normal 

 annual rainfall is remarkably heavy, exceeding that at the nearest 

 station, Wilmington, by 30 centimeters. Only on the coast of Wash- 

 ington and Oregon does the total rainfall within tlie limits of tlie 

 United States notably exceed that of Hatteras. The normal varia- 

 tion between the month of least and that of greatest rainfall does 

 not exceed 5 centimeters, so that in ordinary seasons periods of 

 drought do not occur. The heaviest rainfall occurs in tlie months from 

 July to October. The average number of rainy days is large, about 

 one-third of the days of the year, and is distributed with relatively 

 great uniformity, varying from 6.7 days in the montli of least to 15.9 

 in the month of greatest number of rainy days. 



Of dewfall no statistics could be obtained. 



