TEMPEEATUEB. 



599 



of its fall, for sleighing' and sledding through this whole period of steady 

 cold. This season, too, is more sharply demarked than in most other parts 

 of the United States. It is begun by a sudden cold wave, generally during 

 the first half of November, which freezes the ground aiid stops the late 

 autumn work of plowing; and the return of warmth in spring is by a sud- 

 den transition which rapidly melts away the snow and soon thaws and 

 dries the land sufficiently to prepare it for the seeding of the broad wheat 

 fields. 



The foll'owing table shows the mean temperatures at the six stations 

 before noted. In the United States they were computed from the daily 

 extremes of temperature during a period of nine years preceding the end 

 of 1888. At Winnipeg, Manitoba, the average is drawn from observations 

 begun in 1871 and extending through fifteen years. 



Normal temperature, in degrees Fahrenheit, for each month and for the whole year. 



Ice on the Red River closed the season of navigation at Moorhead 

 and Fargo in the years 1881 to 1888 at dates which range from the 11th 

 to the 25th of November; and navigation Avas opened, with the breaking 

 up and departure of the ice, at dates from the 12th to the 24th of April. 

 Throughout the years 188!) and 1890 navigation was suspended l)ecause of 

 the low stage of water. 



The first severe frosts, destroying tender vegetation, occurred at Moor- 

 head and Fargo in tlie years 1881 to 1890 at dates from August 25 to 

 September 20; and the last severe frost there in spring during the same 

 years ranged i'rom Ma.}' 2 to June 8. At St. Vincent these dates for the 

 first were from August 4 to September 20, and for the last from April 29 

 to June 8. 



