[Sidenote: The Climate of Washington Territory.]
Climate is a matter of temperature, moisture and atmospheric dynamics.
The general law of temperature is that the farther north the colder the
weather; and yet currents of water and prevailing winds may give to the
country a climate geographically belonging to quite a different
latitude. We know how this is with England, which, judged by latitude,
ought to be colder than Maine, but which, in fact, has one of the
mildest and most equable climates in the world. England is farther north
than Washington Territory, which latter is in the latitude of France;
but it is also in the latitude of Montana, Dakota and Maine, States
remarkable for sudden changes and for terrible cold. But it is well
known that our Pacific States, at least on their western borders, have a
temperature free from extremes in both summer and winter. Taking July
and January as the hottest and coldest months, it will be found that the
average temperature at San Francisco and Puget Sound is from 7° to 14°
cooler than it is in the Rocky Mountains and in New England during the
same months. And on the other hand, taking January as the coldest month,
we find that Bismarck, Denver, New England, etc., are 30° to 40° colder
than the points on the Pacific. In other words, that the range of the
thermometer between extremes averages near 50° more in the East than it
does in the West in the localities named; a very great difference when
we consider comfort, health, cost of living, and opportunity to labor
in the open air.
[Sidenote: Mild and equable.]
This greater mildness and equability of temperature on the Pacific Coast
is to be ascribed to the winds and currents of the great ocean. During
the summer the winds come from the northwest, and during the winter from
the southwest and south. Much influence in tempering the cold of winter
is ascribed also to the Japan Current, mentioned under a former head. It
does for the Pacific Coast what the Gulf Stream does for England.
The same causes regulate also the rainfall on the Pacific Coast. In one
respect there is the same peculiarity along the whole coast, namely, dry
summers and, comparatively, wet winters. There is, however, a gradual
increase in the amount of rainfall northward from San Diego to Sitka; so
that when we reach Washington Territory we do not find the excessive
dryness which characterizes the summer climate of California.
[Sidenote: Rainfall.]
The figures of different authorities do not agree exactly as to the
precipitation on the Pacific Coast: for example, in the older volume on
Rain Tables, published by the Smithsonian Institution, the annual
rainfall and melted snow on Puget Sound, measured at Steilacoom, near
Olympia, from 1849 to 1867, amounted to 43.98 inches. Governor Semple,
however, gives from Sergeant McGovern, in charge of the station, a total
of 53.89 inches annually, measured at Olympia from 1878 to 1886. But I
find in the report of the chief signal officer to the War Department for
1884, that the average from July 1, 1877, to December, 1883, for
Olympia, was 62.81 inches. This difference of nine inches is partly
accounted for by the fact that the precipitation in the subsequent years
not included in the report of the Signal Service Bureau, namely, 1884,
1885 and 1886, averaged only 41.88 inches, which would, in great
measure, relieve the discrepancy. It will probably turn out on further
observation that 53 inches is about the total annual rainfall for Puget
Sound. But according to the report of the chief signal officer for 1884,
we have the following annual totals: San Diego, 9.40; San Francisco,
23.32; Portland, Oregon, 54.16; Puget Sound, 62.81; Sitka, Alaska, 97.28
inches.
Comparing these with points farther east, we have Bismarck, Dakota,
21.35; Denver, 14.97; Sandusky, Ohio, 41.43; New Haven, Connecticut,
51.55; Norfolk, Virginia, 52.14 inches.
The value of rainfall depends more on its distribution among the months
than on its annual aggregate. England has but 25 inches rain per annum,
but it comes at such times as makes it most effective. The rains on the
Pacific Coast are not distributed in the most favorable way for
agriculture--the summers being too dry. At San Diego there is less than
one-third of an inch in the three summer months, and still less at San
Francisco. On Puget Sound, for that time, the fall is 2.57. In
Washington Territory the spring rains are as abundant as in the Atlantic
States, and the summer breezes seem laden with moisture.
[Sidenote: No blizzards or cyclones.]
[Sidenote: Differences between East and West Washington.]
In respect to cold waves, winds and storms, Washington Territory is
singularly favored. There is nothing to correspond with the blizzards,
northers, hurricanes and cyclones which trouble some other States. Even
ordinary thunder-storms are rare. The climate of East Washington is
different from that of West Washington, and yet, when compared with that
of Montana and Dakota, it will be seen that it is really transitional
and intermediate between the climates on each side. The range of
thermometer from the heat of July to the cold of January is, at
Bismarck, 65°; at Spokane Falls, 45°, and on Puget Sound, 22°. And, in
like manner, the amount of rain is intermediate between the heavy
rainfall of the Sound and the lighter rains of the Rocky Mountain
country. The explanation of this is, that while the Cascade Range, like
all high mountains, condenses the moisture of the air on the windward
side and changes its temperature, yet this range is not sufficiently
high and cold to have the effect of the Himalayas or the Andes in
depriving the leeward lands of rain.
The mountain rim of the plateau country has not the moisture which
distinguishes the west side of the Cascade, and it varies in its amount
at different places.
Some statements have already been made in reference to the dryness and
summer heat of the Yakima Valley on the east flank of the main mountain.
The mountains running along the Canada line have probably a better
summer climate than the east side of the main mountain. I do not know
how it is with the Coeur d'Alene and Blue Mountains, but the climate
of the plateau has no unusual character in the matter of temperature.
Half of the States of the Union have as great or greater extremes; but
the plateau has less than half the precipitation of Puget Sound, as
shown in the tables given on pages 56 and 57. And the rainfall in the
summer is so scant that one would not, _a priori_, expect any form of
vegetation to progress at all. These meteorological phenomena render
almost unaccountable the facts of agriculture, which will be given
hereafter.
[Sidenote: Chinook wind.]
The Chinook wind, which springs up in winter and melts the snow on the
plateau, and to some extent in the mountains, is simply a southerly
wind, such as is common in the Mississippi Valley and even on the
Atlantic seaboard. In the Pacific States it does not, from the
descriptions, appear to differ from the breezes of the coast, except in
its greater strength and steadiness. I heard an intelligent gentleman,
residing in Spokane Falls, say that he thought the Chinook was a
disadvantage in winter, as it caused a disagreeable thaw, and so relaxed
the human system as to render it more sensitive to cold; but generally
the Chinook is enjoyed in East Washington.