"North of the Aleutian Islands the coast climate becomes more rigorous in winter, but in summer the difference is much less marked.
"The climate of the interior is one of extreme rigor in winter, with a brief but relatively hot summer, especially when the sky is free from cloud.
"In the Klondike region in midwinter the sun rises from 9:30 to 10 a. m., and sets from 2 to 3 p. m., the total length of daylight being about four hours. Remembering that the sun rises but a few degrees above the horizon and that it is wholly obscured on a great many days, the character of the winter months may easily be imagined.
"We are indebted to the United States coast and geodetic survey for a series of six months' observations on the Yukon, not far from the site of the present gold discoveries. The observations were made with standard instruments, and are wholly reliable. The mean temperatures of the months October, 1889, to April, 1890, both inclusive, are as follows: October, 33 degrees; November, 8 degrees; December, 11 degrees, below zero; January, 17 below zero; February, 15 below zero; March, 6 above; April 20 above. The daily mean temperature fell and remained below the freezing point (32 degrees) from Nov. 4, 1889, to April 21, 1890, thus giving 168 days as the length of the closed season of 1889-'90, assuming that outdoor operations are controlled by temperature only. The lowest temperatures registered during the winter were: Thirty-two degrees below zero in November, 47 below in December, 59 below in January, 55 below in February, 45 below in March, and 26 below in April.
"The greatest continuous cold occurred in February, 1890, when the daily mean for five consecutive days was 47 degrees below zero.
"Greater cold than that here noted has been experienced in the United States for a very short time, but never has it continued so very cold for so long a time as in the interior of Alaska. The winter sets in as early as September, when snow-storms may be expected in the mountains and passes. Headway during one of those storms is impossible, and the traveler who is overtaken by one of them is indeed fortunate if he escapes with his life. Snowstorms of great severity may occur in any month from September to May, inclusive.
"The changes of temperature from winter to summer are rapid, owing to the great increase in the length of the day. In May the sun rises at about 3 a. m. and sets about 9 p. m. In June it rises about half past 1 in the morning, and sets at about half past 10, giving about twenty hours of daylight and diffuse twilight the remainder of the time.