from the north off the coast of Southern California, and the mountain ranges from Point Conception east divide the State of California into two climatic regions, the southern having more warmth, less rain and fog, milder winds, and less variation of daily temperature than the climate of Central California to the north.[A] Other striking climatic conditions are produced by the daily interaction of the Pacific Ocean and the Colorado Desert, infinitely diversified in minor particulars by the exceedingly broken character of the region—a jumble of bare mountains, fruitful foot-hills, and rich valleys. It would be only from a balloon that one could get an adequate idea of this strange land.
The United States has here, then, a unique corner of the earth, without its like in its own vast territory, and unparalleled, so far as I know, in the world. Shut off from sympathy with external conditions by the giant mountain ranges and the desert wastes, it has its own climate unaffected by cosmic changes. Except a tidal wave from Japan, nothing would seem to be able to affect or disturb it. The whole of Italy feels more or less the climatic variations of the rest of Europe. All our Atlantic coast, all our interior basin from Texas to Manitoba, is in climatic sympathy. Here is a region larger than New England which manufactures its own weather and refuses to import any other.
With considerable varieties of temperature according to elevation or protection from the ocean breeze, its climate is nearly, on the whole, as agreeable as that of the Hawaiian Islands, though pitched in a lower key, and with greater variations between day and night. The key to its peculiarity, aside from its southern exposure, is the Colorado Desert. That desert, waterless and treeless, is cool at night and intolerably hot in the daytime, sending up a vast column of hot air, which cannot escape eastward, for Arizona manufactures a like column. It flows high above the mountains westward till it strikes the Pacific and parts with its heat, creating an immense vacuum which is filled by the air from the coast flowing up the slope and over the range, and plunging down 6000 feet into the desert. "It is easy to understand," says Mr. Van Dyke, making his observations from the summit of the Cuyamaca, in San Diego County, 6500 feet above the sea-level, "how land thus rising a mile or more in fifty or sixty miles, rising away from the coast, and falling off abruptly a mile deep into the driest and hottest of American deserts, could have a great variety of climates. … Only ten miles away on the east the summers are the hottest, and only sixty miles on the west the coolest known in the United States (except on this coast), and between them is every combination that mountains and valleys can produce. And it is easy to see whence comes the sea-breeze, the glory of the California summer. It is passing us here, a gentle breeze of six or eight miles an hour. It is flowing over this great ridge directly into the basin of the Colorado Desert, 6000 feet deep, where the temperature is probably 120°, and perhaps higher. For many leagues each side of us this current is thus flowing at the same speed, and is probably half a mile or more in depth. About sundown, when the air on the desert cools and descends, the current will change and come the other way, and flood these western slopes with an air as pure as that of the Sahara and nearly as dry.
"The air, heated on the western slopes by the sea, would by rising produce considerable suction, which could be filled only from the sea, but that alone would not make the sea-breeze as dry as it is. The principal suction is caused by the rising of heated air from the great desert. … On the top of old Grayback (in San Bernardino) one can feel it [this breeze] setting westward, while in the cañons, 6000 feet below, it is blowing eastward. … All over Southern California the conditions of this breeze are about the same, the great Mojave Desert and the valley of the San Joaquin above operating in the same way, assisted by interior plains and slopes. Hence these deserts, that at first seem to be a disadvantage to the land, are the great conditions of its climate, and are of far more value than if they were like the prairies of Illinois. Fortunately they will remain deserts forever. Some parts will in time be reclaimed by the waters of the Colorado River, but wet spots of a few hundred thousand acres would be too trifling to affect general results, for millions of acres of burning desert would forever defy all attempts at irrigation or settlement."
This desert-born breeze explains a seeming anomaly in regard to the humidity of this coast. I have noticed on the sea-shore that salt does not become damp on the table, that the Portuguese fishermen on Point Loma are drying their fish on the shore, and that while the hydrometer gives a humidity as high as seventy-four, and higher at times, and fog may prevail for three or four days continuously, the fog is rather "dry," and the general impression is that of a dry instead of the damp and chilling atmosphere such as exists in foggy times on the Atlantic coast.
"From the study of the origin of this breeze we see," says Mr. Van Dyke, "why it is that a wind coming from the broad Pacific should be drier than the dry land-breezes of the Atlantic States, causing no damp walls, swelling doors, or rusting guns, and even on the coast drying up, without salt or soda, meat cut in strips an inch thick and fish much thicker."
At times on the coast the air contains plenty of moisture, but with the rising of this breeze the moisture decreases instead of increases. It should be said also that this constantly returning current of air is always pure, coming in contact nowhere with marshy or malarious influences nor any agency injurious to health. Its character causes the whole coast from Santa Barbara to San Diego to be an agreeable place of residence or resort summer and winter, while its daily inflowing tempers the heat of the far inland valleys to a delightful atmosphere in the shade even in midsummer, while cool nights are everywhere the rule. The greatest surprise of the traveller is that a region which is in perpetual bloom and fruitage, where semi-tropical fruits mature in perfection, and the most delicate flowers dazzle the eye with color the winter through, should have on the whole a low temperature, a climate never enervating, and one requiring a dress of woollen in every month.
[A] For these and other observations upon physical and climatic conditions I am wholly indebted to Dr. P. C. Remondino and Mr. T. S. Van Dyke, of San Diego, both scientific and competent authorities.
CHAPTER II.
OUR CLIMATIC AND COMMERCIAL MEDITERRANEAN.
Winter as we understand it east of the Rockies does not exist. I scarcely know how to divide the seasons. There are at most but three. Spring may be said to begin with December and end in April; summer, with May (whose days, however, are often cooler than those of January), and end with September; while October and November are a mild autumn, when nature takes a partial rest, and the leaves of the deciduous trees are gone. But how shall we classify a climate in which the strawberry (none yet in my experience equal to the Eastern berry) may be eaten in every month of the year, and ripe figs may be picked from July to March? What shall I say of a frost (an affair of only an hour just before sunrise) which is hardly anywhere severe enough to disturb the delicate heliotrope, and even in the deepest valleys where it may chill the orange, will respect the bloom of that fruit on contiguous ground fifty or a hundred feet higher? We boast about many things in the United States, about our blizzards and our cyclones, our inundations and our areas of low pressure, our hottest and our coldest places in the world, but what can we say for this little corner which is practically frostless, and yet never had a sunstroke, knows nothing of thunder-storms and lightning, never experienced a cyclone, which is so warm that the year round one is tempted to live out-of-doors, and so cold that woollen garments are never uncomfortable? Nature here, in this protected and petted
