Shkoder Northern coastal lowlands 50 59 40 78 80 Durres Central coastal lowlands Sea level 61 47 77 38 Vlore Southern coastal lowlands do 62 48 77 39 Sarande Albanian Riviera do 63 ... ... 55 Tirana Mid-Albania at base of central uplands 360 58 42 76 49 Puke North-central uplands 2,850 51 34 70 72 Kruje Central uplands 2,000 55 39 71 67 Korce Eastern highlands 2,850 51 ... ... 30 *In degrees Fahrenheit. Source: Adapted from _Vjetari Statistikor i R. P. Sh., 1967-1968_. Tirana, 1968, pp. 18-19; and Great Britain, Admiralty, Naval Intelligence Division, _Albania_, London, 1945, p. 93. When the continental system is weak, Mediterranean winds drop their moisture farther inland. When there is a dominant continental air mass, it spills cold air onto the lowland areas. This occurs most frequently in the winter season. Since the season's lower temperatures damage olive trees and citrus fruits, their groves and orchards are restricted to sheltered places with southern and western exposures, even in areas that have seemingly high average winter temperatures. Lowland rainfall averages from forty to nearly sixty inches annually, increasing between those extremes from south to north. Nearly 95 percent of the rain falls during the rainy season. Rainfall in the upland mountain ranges is higher. Adequate records are not available, and estimates vary widely, but annual averages are probably about 70 inches and are as high as 100 inches in some northern areas. The seasonal variation is not quite as great as in the coastal area, with the most nearly even distribution in the north, largely because of summer thunderstorms. The higher inland mountains receive less precipitation than the intermediate uplands. Terrain differences cause wide local variations, but the seasonal distribution is the most consistent of any area. In the northern mountains, for example, the months that usually have the highest averages are November and June. DRAINAGE