36 The Climate of Peoria. 
Winter Spring. Summer Fall 
FeOria son... > dom Di Ak Ge cksdaesveun. DED. Bees. ccocbavee ddd, stands. Been 58.2 
Paris: >zc8s. ce B8.0i68..: sacs Panes HOS Sie csesten os 64.6 Shey... cae 52.5 
Difference ... 8.9 0.7 10.9 + 0.7 
Rome, in Italy, about one degree farther north than Peoria has a mean tem- 
perature of 60.8, in summer 74.3 in winter 50. That makes the mean temper- 
ature of Rome about 9 degrees and in winter 22.6 degrees warmer than at 
Peoria, and the summer is nearly one degree cooler. These examples may be 
sufficient to show the difference of the climate of western Europe and that of 
the central part of North America. 
WINTER. 
The three winter months together had the lowest mean 20.7 in the winters 
from 1872 to 1878, and 1874 to 1875. Above freezing point was the mean of 
the winters 1862-68, 1875-76, 1877-78, and 1879-80; in all the rest it was be- 
low freezing point. The coldest January was that of 1857 (13.5), the coldest 
February 1875 (15.5), the coldest December 1876 (18.5). The warmest Jan- 
uary was in 1880 (40.9), the warmest February 1878 (37.5), the warmest De- 
cember 1877 (44.3). The coldest decade in Jamuary was 1864, 1st-10th (0.2) 
in February 1875, 11th-20th (8) and in December 1872, 21st-31st, (8.8). The 
warmest decade in January was in 1864, 21st—31st, (41.8), in February 1871, 
2ist-28th, (41.2), in December 1862, 21st-31st, (41.7). 
When we call the three months December, January and February the three 
wintermonths, it is obvious that this is mere theory, Practically winter is 
not restricted to those three months; there are no general limits which are 
good for every year. When we take freezing as a distinctive quality of win- 
ter we find its limits very variable in different years. The mercury is falling 
below freezing point in a period commencing on the 1st of October and end- 
ing on the 11th of May, so that the first frost days in the thirty years occurred 
between the Ist of October and the 12th of November, the last between the 
25th of March and 11th of May. The longest of those periods was that in the 
winter from 1856 to 1857; the first frost was noticed on the Ist of October and 
the last on the 11th of May, a period of 223 days; the shortest was that from 
the 3d of November 1877, to the 25th of March 1878, a period of 148 days. 
The former contained 142, the latter only 51 frost days. Computing the aver- 
ages we find the first frost day to be the 17th of October,. for the last frost day 
the 17th of April, a period of 138 days with 112 frost days and 48 days with 
a mean temperature not rising above freezing point. 
SPRING. 
The mean temperature of the three spring months together is 50.2. The 
lowest mean was observed in 1857, —43, the highest in 1878 =56.6. The 
coolest March was in 1867 —29.5; the coolest April in 1857 =89.9; the cool- 
est May 1867 —55; the warmest March 1878 —50.5; the warmest April 1878 
' =57.9; the warmest May 1881 =71.4. The mean temperature of the decades 
are in March, Ist =385; 2d —37; 3d —41.8, The lowest was the first in 1857 
22.3; the highest the first in 1878 =52.5; in April the lst 47.8; 2d 51.7; 
3d 55.5. The lowest the Ist in.1881 =32.7; the highest the 3d in 1879 =66.2; 
in May the first =59.9, the 2d —63.3, the 3d 67.9; the lowest the 1st in 
1867 =51.1; the highest the 8d in 1881 =—77. The highest mean temperature 
of a single day of March was in 1875 on the 30th =65.6; of April in 1872 on the 
29th =77; of May in 1860 on the 24th =85.1; the lowest of March in 1867 on 
the 13th =4.7; of April in 1857 on the 6th =13.7; of May in 1875 on the Ist 
