142 



IOWA DEPARTMENT OF AGRICULTURE. 



KEOKUK FROST DATA-Continued. 



SIOUX CITY FROST DATA. 



1890. 

 1891. 

 1892. 

 189;^. 

 1894. 

 1895. 



1897. 

 1898. 

 1899. 

 1900. 

 1901. 

 1902. 



Averages. 



May.. 

 April. 

 May . 

 May . 

 May . 

 May . 

 April 

 April 

 April 

 May . 

 May . 

 April 

 April 



May . 



September . 

 September. 

 October . . . 

 October . . . 

 September. 

 September. 

 September. 

 September. 

 September. 

 October . . . 

 September. 

 September. 

 September. 

 September. 



1 September. 



129 

 182 

 154 

 146 

 134 

 129 

 153 

 141 

 163 

 139 

 136 

 150 

 143 



145 



SUNSHINE AND CLOUDINESS. 



Iowa enjoys the advantage of a good average amount of sunshine. The 

 mean for the year is 50 to 60 per cent, and this average is maintained in 

 midwinter as well as in midsummer. A distinctive feature of the climate as 

 compared with the eastern states is the large percentage of clear skies in the 

 winter season. The coldest periods in winter are generally cloudless, as a 

 result of the low percentage of humidity during prevalence of north and 

 west winds. For the year the average for the state is as follows: 156 clear, 

 107 partly cloudy, and 102 cloudy days. The following table shows the 

 yearly averages for the state from 1892 to 1902, inclusive. It wil^ be seen 

 that in the hot and dry years, 1894 and 1901, the number of clear days 

 much exceeded the normal: 



DESTRUCTIVE STORMS. 



Cyclones of the transcontinental type, which move in rapid succession 

 across this central valley and irrigate the larger part of the continent, are 



