Climate of Middle Illinois. 



SEE ERRATA 

 25 



How great the influence of insolation must be upon the growth of 

 plants is shown by the difEerence of the thermometer in the shade and 

 exposed to the sun, which, in June, often exceeds 20 degrees and more yet 

 in winter. 



PEE. CENT. OF COVERING. 



Y A.M. 



2 p.m. 



Mean. 



NUMEMB OF DAYS 



Cloud- 

 less. 



Moder- 

 ately 

 cloudy. 



■Very 

 cloudy. 



With- 

 out sun 

 shine. 



SUNSHINE. 



Hours. 



per ct. 



December 

 January .. 

 February . 



Miirch 



April 



May 



. June 



July 



August . . . 

 September 

 ■October... 

 November 



Winter . . . 



Spring 



Summer . . 

 Tall 



Year 



59 

 57 

 52 

 53 

 51 

 45 

 44 

 37 

 37 

 44 

 47 

 55 



56 

 49 

 39 



48 



48 



54 

 56 

 55 

 56 

 57 

 50 

 48 

 47 

 45 

 45 

 46 

 56 



55 

 54 

 47 

 49 



51 



53 

 48 

 49 

 49 

 45 

 35 

 32 

 29 

 27 

 31 

 35 

 49 



50 

 43 

 29 

 39 



40 



55 

 54 

 52 

 52 

 51 

 43 

 41 

 38 

 35 

 40 

 43 

 53 



54 

 49 

 38 

 45 



47 



4 

 4 

 3 

 3 

 2 

 3 

 2 

 2 

 4 

 4 

 6 

 3 



11 

 8 

 7 



13 



39 



10 

 10 

 11 

 12 

 11 

 13 

 16 

 18 

 18 

 14 

 12 

 10 



31 

 37 

 52 

 36 



156 



17 

 17 

 14 

 16 

 16 

 15 

 12 



n 



10 

 12 

 13 

 17 



48 

 47 

 33 

 42 



170 



10 



26 



14 



3 



16 



59 



129 

 133 

 149 

 182 

 192 

 269 

 315 

 314 

 299 

 216 

 202 

 148 



411 

 643 

 929 

 566 



2550 



45 

 46 

 51 

 50 

 49 

 61 

 71 

 69 

 71 

 58 

 59 

 51 



48 

 53 

 70 

 56 



WIND. 



West winds are prevalent from October to April. South winds dur- 

 ing the summer; only in August east equals the south. About 12 p. m. 

 of all the observations are marked as high winds, gales or hurricanes, but 

 the force of winds were not measured by the anemometer but only esti- 

 mated, and the dates are not quite reliable. 



The windiest months are March and April; the calmest, August and 

 September. 



Wind and temperature, wind and cloudiness, wind and precipitation 

 are, in a certain degree, correlative. The warmest winds are south, south- 

 west and east; the coldest, northwest, north and northeast. The difEerence 

 between the coldest and warmest winds is about 15, in spring even 20 de- 

 grees. Above the average is the temperature with south and southwest 

 in all the months, with east only in spring and fall. Southeast wind is 

 too scarce, so that no reliable mean could be abstracted. The temperature 

 of north is always below. Northeast is only in November, December and 

 January above, and that may be accounted for by the great quantity of 

 cloudiness that always accompanies these winds, preventing radiation. 

 Northwest has only, in August, a temperature above average. The region 

 from which this wind come is naturally a cold one, only during the sum- 

 4 



