Recent in-depth studies of satellite imagery and environmental analysis regarding forest classification conclude that Haiti actually has approximately 30% tree cover; this is, nevertheless, a stark decrease from the country's 60% forest cover in 1925. The country has been significantly deforested over the last 50 years, resulting in the desertification of portions of the Haitian territory. In the Dominican Republic, the forest cover has increased. In 2003, the Dominican forest cover had been reduced to 32% of the territory, but by 2011, forest cover had increased to nearly 40%. The success of the Dominican forest growth is due to several Dominican government policies and private organizations for the purpose, and a strong educational campaign that has resulted in increased awareness on the Dominican people of the importance of forests for their welfare and in other forms of life on the island. Owing to its mountainous topography, Hispaniola's climate shows considerable variation over short distances, and is the most varied of all the Antilles. Except in the Northern Hemisphere summer season, the predominant winds over Hispaniola are the northeast trade winds. As in Jamaica and Cuba, these winds deposit their moisture on the northern mountains, and create a distinct rain shadow on the southern coast, where some areas receive as little as of rainfall, and have semi-arid climates. Annual rainfall under also occurs on the southern coast of Haiti's northwest peninsula and in the central Azúa region of the Plaine du Cul-de-Sac. In these regions, moreover, there is generally little rainfall outside hurricane season from August to October, and droughts are by no means uncommon when hurricanes do not come. On the northern coast, in contrast, rainfall may peak between December and February, though some rain falls in all months of the year. Annual amounts typically range from on the northern coastal lowlands; there is probably much more in the Cordillera Septentrional, though no data exist. The interior of Hispaniola, along with the southeastern coast centered around Santo Domingo, typically receives around per year, with a distinct wet season from May to October. Usually, this wet season has two peaks: one around May, the other around the hurricane season. In the interior highlands, rainfall is much greater, around per year, but with a similar pattern to that observed in the central lowlands. As is usual for tropical islands, variations of temperature are much less marked than rainfall variations, and depend only on altitude. Lowland Hispaniola is generally oppressively hot and humid, with temperatures averaging . with high humidity during the daytime, and around at night.