CLIMATE AND SOIL. Alaska varies in climate and soil according to the divisions above noted, and according to altitude and nearness to or remoteness from the sea. The climate of the south coast region. however, is so modified by the shielding mountains and the presence of the ocean (where the Japan current flows along the coast from the eastward) that. this part of Alas ka may be called temperate. and its climate aim productions. as far north as Sitka, at least, differ little from those of British Columbia. The isotherm of 40° mean annual temperature, which passes through the lower St. Lawrence Valley on the eastern side of the continent, curves north ward west of the Pocky Mountains, and is the mean annual isotherm of the southern Alaskan coast region: but the climate of this region ex hibits less extremes between winter and summer temperature than does that of the St. Lawrence Valley, and is far more rainy, as must neces sarily he the ease where the prevailing winds come off the ocean and almost immediately strike against snowy mountains; which condense and precipitate their moisture almost incessantly. Days without rain are rare, and fogs prevail. These conditions so modify the temperature of the coast that the mercury rarely descends below zero or rises above 80° P. Much the same temperature exists over Kadiak Island and the Aleutian chain, but with greater cold and more wind and snow in winter. Cook's Inlet has the
agreeable peettliality of being almost free of the fogs so prevalent elsewhere. North of the moun tains, where the country is barrieaded against the tempering influence of the Pacific and ex posed to the northern winds, lower temperature and drier conditions prevail.
Data for the Nuskokwim division are scanty, hut indicate that the average for midwinter ap proaches zero and for midsummer about 50°. In the lower Yukon Valley send-arctic conditions prevail, a brief, warm summer, averaging about ;0° F. for July, being followed by a lung winter of excessive cold, the average temperature from December to March at Nttlato being about 16° below zero, with frequent "spells" of —40° to —50° F. It is colder further up the river, where navigation is limited to three months. (See YUKON.) At St. Michael's Island and on the neighboring coast (Nome) of Norton Sound, the temperature is more moderate than in the inte rior, the winter being less protracted and severe. Along the northern coast the climate is truly arctic, the annual mean at Point Barrow !wing about 25° F. The northern interior, wherever level, is swampy. and the soil is permanently frozen a curd ur so below the surface. In the southerly half of Alaska. at least, the soil is fertile enough, so far as its qualities go.