California," wrote Captain William Shaler, "generally is dry and temperate, and remarkably healthy; on the western coast the sky is generally obscured by fogs and haze, but on the opposite side it is constantly clear; not a cloud is to be seen, night or day. The northwest winds blow very strong eight months in the year, on the western coast, with very little interruption; the land breezes at that time are hardly perceptible; but in the winter months they are stronger and regular. In the months of January, February, and March there are at times very high gales from the southeast, which render most of the bays and harbours on the coast unsafe at that season."
California's climate is characterized by certain peculiar features: the temperature of the entire Pacific Coast is milder and more uniform than that of regions in corresponding latitudes east of the mountains; the year divides, in general, into two seasons—wet and dry—instead of into the usual four seasons; and where extreme summer heat occurs, its discomfort is lessened by the dryness of the air.
Despite these general characteristics the State is a place of many climates, due to distance from the ocean, situation in reference to mountains, and, above all, altitude. Thus there are sharp climatic contrasts within a single limited area. One may go sleighing within sight of blossoming orchards, or view snow-clad peaks while bathing in the sea. A winter traveler in the high Sierra will be reminded of the Alps, while anyone venturing into the scorching inland valleys in midsummer will conclude that whoever labeled California "semitropical" was a master of understatement.
The term, however, is applied with good reason to the strip of land between the coastal mountains and the ocean. For those who have never visited this area the most restrained account of its climate is likely to seem hyperbole. The year-round weather is more equable than that of any other part of the United States; and from San Francisco southward to Monterey, the difference between the average summer and winter temperatures is seldom more than 10 degrees. In this coastal region frost heavy enough to halt the greening of the hills under winter rains is as rare as thunder and lightning; and always some flowers are in bloom. Sea breezes and fogs tend to stabilize the temperature without extremes of heat or cold.
The annual mean temperature of San Francisco is 56°; the summer mean is less than 60°, the winter 51°, and the lowest recorded temperature 27°. In San Diego the winter mean temperature is 54°, the summer 68°. In Monterey the difference between January and August mean temperatures is from 10° to 14°; in Los Angeles 14° to 16°. Because of the California current and the marine air from the Pacific anticyclone, summer in San Francisco is actually cooler than fall. These same factors induce fogs, night and morning, in that region and all
