The climate is trying. The west winds are violent during the greater part of the year, especially on the coast, and merely relax a little in the winter. The mean temperature on the Atlantic coast falls nearly one degree for each degree of latitude (14.6 deg. at San Antonio, below 41 deg. S. lat.; 8.5 deg. at Santa Cruz, below 50 deg. S. lat.; and 5.3 deg. at Ushuaia, below 55 deg. S. lat.). The summer temperature falls even more steeply, but the difference is less notable in winter (21.4 deg. at San Antonio, 14 deg. at Santa Cruz, and 9.2 deg. at Ushuaia). The low summer temperature does not allow cereals to ripen south of the Chubut. In the sub-Andean valleys the summer is comparatively warm (16 deg. in January at Diez y seis de Octubre at a height of 1,800 feet), but there is severe frost, especially at the beginning of the winter, and no month of the year is quite free from it. Rain is plentiful in the Cordillera, and on its western border: 800 millimetres at Junin, nearly two metres at San Martin (which the wet westerly winds reach by the gap of Lake Lacar), and nearly a metre at Bariloche, on Lake Nahuel Huapi. It diminishes rapidly, however, as soon as one leaves the mountainous region and goes further east over the tableland. The whole tableland has a rainfall of less than 200 millimetres (Las Lajas 180, Limay 150, San Antonio 180, Santa Cruz 135). It is only south of the Rio de Santa Cruz that the rainfall rises once more (Gallegos 400 millimetres, Ushuaia 500 millimetres). Hence Patagonia as a whole is, with the exception of a narrow belt at the foot of the Andes, a semi-arid region with a sub-desert climate. In the Patagonian Andes the rain falls, as on the coast of Chile, mainly in winter. Between Mendoza, which has the summer-rain feature of central and tropical Argentina, and Chosmalal, in the Neuquen Andes, the contrast is absolute. The summer months there (January and February) are dry, and the rain is confined to the winter months, from May to August. It is the same further south, at Bariloche and at Diez y seis de Octubre. On the Atlantic coast the winter-rain feature is less regular and uniform. At San Antonio the heaviest rains fall in autumn (April and May). There is a secondary maximum in August, and a few more showers in the spring (September and October). South of San Antonio the winter maximum, which is always marked, is cut by a short dry period (July and August at Camerones, June at Deseado and Santa Cruz).[50] In the interior, on the other hand, the winter-rain system remains unchanged. The predominance of the precipitations of the cold season is of great importance to the breeders. As a rule, they come down in the form of snow, which melts slowly, and the small quantity of moisture is at least all absorbed in the soil. South of the Santa Cruz the humidity increases, but the rainy season alters. At Gallegos the wettest month is December; at Ushuaia, the rains last from September to March. The