The climate of Georgia is extremely diverse, considering the nation's small size. There are two main climatic zones, roughly separating Eastern and Western parts of the country. The Greater Caucasus Mountain Range plays an important role in moderating Georgia's climate and protects the nation from the penetration of colder air masses from the north. The Lesser Caucasus Mountains partially protect the region from the influence of dry and hot air masses from the south as well.
Much of western Georgia lies within the humid subtropical zone with annual precipitation ranging from 1000-4000 mm (39-157 inches). The precipitation tends to be uniformly distributed throughout the year, although the rainfall can be particularly heavy during the autumn months. The climate of the region varies significantly with elevation and while much of the lowland areas of western Georgia are relatively warm throughout the year, the foothills and mountainous areas (including both the Greater and Lesser Caucasus Mountains) experience cool, wet summers and snowy winters (snow cover often exceeds 2 meters in many regions). Adjara is the wettest region of the Caucasus, where the Mt. Mtirala rainforest, on the east of Kobuleti receives around 4500 mm (177 inches) of precipitation per year.
Eastern Georgia has a transitional climate from humid subtropical to continental. The region's weather patterns are influenced both by dry, Central Asian/Caspian air masses from the east and humid, Black Sea air masses from the west. The penetration of humid air masses from the Black Sea is often blocked by several mountain ranges (Likhi and Meskheti) that separate the eastern and western parts of the nation. Annual precipitation is considerably less than that of western Georgia and ranges from 400-1600 mm. (16-63 inches). The wettest periods generally occur during spring and autumn while winter and summer months tend to be the driest. Much of eastern Georgia experiences hot summers (especially in the low-lying areas) and relatively cold winters. As in the western parts of the nation, elevation plays an important role in eastern Georgia as well, and climatic conditions on 1500 meters (4920 ft.) above the sea level are considerably cooler (even colder than those of the low-lying areas.) The regions that lie above 2000 meters (6560 ft.) above the sea level frequently experience frost even during summer months.