Northern Algeria lies within the temperate zone, and its climate is similar to that of other Mediterranean countries, although the diversity of the relief provides sharp contrasts in temperature. The coastal region has a pleasant climate, with winter temperatures averaging from 10° to 12° C (50° to 54° F ) and average summer temperatures ranging from 24° to 26° C (75° to 79° F ). Rainfall in this region is abundant—38 to 69 cm (15 to 27 in) per year, and up to 100 cm (40 in) in the eastern part—except in the area around Oran (Ouahran), where mountains form a barrier against rain-carrying winds. When heavy rains fall (often more than 3.8 cm/1.5 in within 24 hours), they flood large areas and then evaporate so quickly that they are of little help in cultivation.
Farther inland, the climate changes; winters average 4° to 6° C (39° to 43° F ), with considerable frost and occasional snow on the massifs; summers average 26° to 28° C (79° to 82° F ). In this region, prevailing winds are westerly and northerly in winter and easterly and northeasterly in summer, resulting in a general increase in precipitation from September to December and a decrease from January to August; there is little or no rainfall in the summer months.
In the Sahara Desert, temperatures range from –10° to 34° C (14° to 93° F ), with extreme highs of 49° C (120° F ). There are daily variations of more than 44° C (80° F ). Winds are frequent and violent. Rainfall is irregular and unevenly distributed.