METEOROLOGY CLIMATOLOGY . 281 



May is the wettest nioiitli. The rainfall of the eeutral distiict i.s oS.Ol in. The least 

 rainfall was 22.S5 in. in 1S79, the greatest, 48.67 in. in 187(3. Eigliteen and eight- 

 tenths per cent of the total rainfall occurs in winter, 29.7 per cent in spring, 28.9 

 percent in summer, and 22.6 per cent in autumn. May has heaviest rainfall. The 

 rainfall of the southern district is 42. 19 in. The least was 30.05 in. in 1872, the great- 

 est, 55.68 in. in 1882. About 21.6 per cent falls in winter, 30.6 per cent in spring, 

 26 per cent in summer, and 21.8 per cent in autunui. March has most rain. 



"The average rainfall for the State is 37.39 in. The least was 25 in. in 1901, the great- 

 est, 47.39 in. in 1898. Six northern counties have 11.3 in. less than seven southern 

 counties. The Ozark Ridge in the southern part of the State makes the rainfall of 

 the counties in which it is situated 7.15 in. more than those immediately above the 

 ridge. A rainy region is situated along the Wabash River up as far as Crawford 

 County. The average temperature for the State is 52.3° F. Northern tier of coun- 

 ties 46.9°, southern counties 57.6°. Northern summers are 7° cooler than southern, 

 while northern winters are 17.2° cooler. 



" The average temperature for the northern district is 48.9°. January is the cold- 

 est month, 22.1°; July is the hottest, 74.6°. Lowest temperature recorded, 31° below 

 zero. The extreme range of temperature is 143°; average annual range about 115°. 

 Highest temperature in summer of 1901. The average temperature for the central 

 district is 52.7°, the extreme range being 139°; the average annual range being about 

 109°. Lowest temperature recorded was 28° below zero in 1884; highest, 112° in 1901. 

 The average temperature for the southern district, 55.9°. Lowest temperature 

 observed was 23° below zero, in February, 1899, the highest being 115° in 1901. 

 Extreme range is 138°, with average annual range about 103°. 



"The average date for the last killing frost in spring is 15 days later in northern 

 than in southern part, and the date for the first killing frost in fall is 12 days earlier 

 than in the southern. The difference between dates of last killing and first killing 

 frosts for extreme parts of State is 40 days. 



"November, December, January, February, March, and April are the cloudy 

 months of the year, being cloudy for 56 per cent of the daylight in the northern, 53^ in 

 each of the other sections. The other months of the year are less cloudy, having 45^ 

 per cent in the northern, 40J in the central, and 42 per cent in the southern. Decem- 

 ber is the cloudiest month for the northern and southern parts, and March for the 

 central part." 



Wet and dry seasons in California, A. G. McAdie ( U. S. Depi. Agr. Yearbaok 

 1902, jjp. 1S7-204, pi. 1, figs. 7). — The available data for rainfall during the rainy 

 season are compiled and discussed with reference to permanent change or periodicity 

 in rainfall. " There does not appear to be any evidence of a permanent change in 

 climate. Wet and dry seasons come and go with little regularity. A deficiency in 

 rainfall seldom extends over two seasons, and the same is true of excessive rainfall." 



Rainfall and irrigation, E. A. Beals ( U. S. Dept. Agr. Yearbook 1902, pp. 627- 

 642, figs. 6). — A discussion of the amount and distribution of rainfall in different 

 parts of the world with reference to the utilization of the water in irrigation. 



Climate of the forest-denuded portion of the Upper Lake region, W. L. 

 ]\IooRK ( f '. >S'. Dcpt. Agr. Yearbook 1902, jij). 125-132, pL 1). — "The tlistinguishing 

 features of the climate of the Upper Lake States may be summed up about as follows: 

 The winter climate is cold and dry, but there is considerable snow in the northern 

 and eastern districts. The transition seasons, spring and autumn, are characterized 

 l)y frequent alternations of clear, fair skies and cloudy, rainy, or snowy weather. 

 The fluctuations of temperature are at times sharp. The summer is warm, with long 

 days and short, cool nights. The rainfall is generally fairly abundant and nuich 

 more constant than is the case to the west and southwest. The hot, desiccating 

 winds that so often wither and kill the growing crops of the Lower Missouri and 



9330— No. 3—03 3 



