Lebanon occupies 10,452 square kilometers on the eastern Mediterranean coast, making it smaller than Connecticut. The country extends 217 kilometers north to south and varies between 32 and 88 kilometers east to west. Its Mediterranean coastline measures 225 kilometers from the Syrian border in the north to the Israeli border in the south.
The country divides into four distinct longitudinal zones running parallel to the coast. The narrow coastal plain rarely exceeds 6 kilometers in width. The Mount Lebanon range rises immediately inland, reaching 3,088 meters at Qurnat as Sawda, the highest point in the Levant outside Turkey. The Beqaa Valley forms a plateau between the Mount Lebanon and Anti-Lebanon ranges at elevations between 900 and 1,000 meters. The Anti-Lebanon Mountains mark the eastern border with Syria, culminating at Mount Hermon (2,814 meters), though Lebanon claims only the western slopes.
The Litani River, Lebanon's only major river entirely within its borders, flows 170 kilometers northward through the Beqaa Valley before turning sharply west to reach the Mediterranean near Tyre. The river drains approximately 2,000 square kilometers but carries minimal water during summer months. Seasonal streams descend from both mountain ranges, flooding briefly after winter storms then vanishing by June.
Mount Lebanon contains several named sub-regions. The Qadisha Valley cuts through limestone formations north of Bcharre, creating gorges up to 1,500 meters deep. The Chouf District occupies the southern section of the Mount Lebanon range southeast of Beirut. The Keserwan District extends along the western slopes northeast of the capital. Each region developed distinct microclimates based on elevation and exposure.
Lebanon's Mediterranean climate divides sharply by altitude. Coastal areas including Beirut, Tripoli, Sidon, Tyre, Byblos, Jounieh, and Batroun receive 750-900 millimeters of annual precipitation, concentrated between November and March. Temperatures at sea level average 13°C in January and 28°C in August. Humidity remains above 70 percent year-round along the coast.
The Mount Lebanon range receives substantially more precipitation, with western slopes collecting 1,200-1,800 millimeters annually. Snow covers areas above 1,500 meters from December through April. Bcharre, at 1,400 meters elevation, records snow depths exceeding 2 meters in average winters. The Cedars of God forest sits at 1,900 meters elevation where snowpack persists into May.
The Beqaa Valley demonstrates continental characteristics despite proximity to the Mediterranean. Zahle and Baalbek receive 400-600 millimeters of precipitation annually. Summer temperatures exceed 35°C regularly, while winter nights drop below freezing. The valley floor produces no natural tree coverage due to the precipitation shadow effect created by Mount Lebanon.
Temperature variance increases dramatically with altitude. For every 100 meters of elevation gain, average temperature drops approximately 0.6°C. This produces a theoretical temperature difference of 18°C between Beirut and Qurnat as Sawda. Winter skiing operates at elevations above 1,800 meters from December through March at six locations along the Mount Lebanon range.
Precipitation patterns show extreme variability between years. Beirut's annual rainfall has ranged from 430 millimeters in drought years to 1,320 millimeters in wet cycles. The Lebanese Meteorological Service recorded the wettest year in 1991-92 and the driest in 2013-14. No reliable long-term cycle has been identified, though multiyear droughts occurred in 1998-2001 and 2013-2014.
Lebanon experiences distinct winds. The southwestern maritime wind brings moisture from October through May. The hot dry "khamsin" wind blows from the Arabian interior during transitional seasons, raising temperatures 10-15°C within hours. Winter easterly winds from continental Syria bring the coldest temperatures to the Beqaa Valley and can penetrate through mountain passes to affect coastal zones.
The Mediterranean coastline alternates between sandy beaches and rocky headlands. Pigeon Rocks at Raouché form twin limestone karst formations rising 60-70 meters offshore from western Beirut. The Palm Islands Reserve protects three small islands 5.5 kilometers northwest of Tripoli. No natural deepwater harbors exist along the Lebanese coast; all ports required artificial breakwater construction.
Coastal geomorphology reflects underlying geology. The northern coast from Tripoli to the Syrian border consists primarily of sandstone formations producing broad beaches. South of Beirut, harder limestone dominates, creating rocky shorelines with occasional pocket beaches. Tyre preserves ancient harbor installations where Phoenician engineers modified natural rock formations.
Lebanon sits along the Dead Sea Transform fault system, a left-lateral strike-slip boundary between the Arabian and African plates. The Yammouneh Fault runs the length of the Beqaa Valley, producing earthquakes that have destroyed cities repeatedly. Historical records document major seismic events in 551 CE (destroying Baalbek and coastal cities), 1202 (affecting Tyre and Sidon), and 1759 (damaging the Beqaa Valley). Seismologists at the Lebanese National Council for Scientific Research measure continuous microseismic activity but no earthquakes above magnitude 6.0 have occurred since instrumental monitoring began in 1910.
Groundwater systems differ fundamentally between the limestone mountains and the alluvial Beqaa Valley. The Mount Lebanon and Anti-Lebanon ranges consist of Jurassic limestone and dolomite formations that create extensive karst aquifer systems. Jeita Grotto, located 18 kilometers north of Beirut, contains an underground river that provides Beirut's primary water supply. The cavern system extends at least 9 kilometers with chambers reaching 120 meters in height. Qammouaa Grotto near Batroun demonstrates similar formations on a smaller scale.
The Beqaa Valley contains unconsolidated sediments up to 1,000 meters deep in places, creating productive aquifers heavily exploited for agriculture. Water table levels have declined 15-20 meters since 1975 according to measurements by the Litani River Authority. Artesian springs historically emerged along the base of Mount Lebanon where karst aquifers intersect impermeable Cretaceous formations, but many ceased flowing after intensive pumping began in the 1980s.
Lebanon contains three recognized climate zones under the Köppen classification system. The coastal strip exhibits Csa characteristics: hot dry summers and mild wet winters. The Mount Lebanon range above 1,200 meters demonstrates Csb climate: warm dry summers and cold wet winters with substantial snowfall. The Beqaa Valley shows transitional characteristics between Mediterranean and semi-arid (BSk) classifications, with cold winters and low total precipitation.
Vegetation zones align with climate and altitude. The coastal zone historically supported maquis shrubland dominated by Palestinian buckthorn, Phoenician juniper, and carob trees, though urbanization has eliminated most natural coverage. Between 400 and 1,400 meters, the Mount Lebanon range once sustained mixed oak-cedar-fir forests. The Lebanon cedar (Cedrus libani) now survives in isolated groves totaling approximately 2,000 hectares.
The Cedars of God forest near Bcharre contains roughly 375 trees across 102 hectares at elevations between 1,900 and 2,300 meters. UNESCO designated this grove a World Heritage Site in 1998. Individual trees reach 35 meters in height with trunk diameters exceeding 2.5 meters. Dendrochronological studies indicate the oldest specimens exceed 1,000 years, though none have been definitively dated beyond 1,200 years. The Tannourine Cedar Reserve protects approximately 600 hectares containing younger cedar stands at 1,500-2,000 meters elevation. The Chouf Cedar Reserve encompasses the largest remaining cedar population, with approximately 300,000 trees across 550 square kilometers of the southern Mount Lebanon range.
Above 2,000 meters, vegetation transitions to alpine meadows and cushion plants adapted to shallow soils and six-month snow cover. Endemic species include Lebanon violet (Viola libanotica) and a regional subspecies of juniper. The Anti-Lebanon range supports sparser vegetation due to lower precipitation and greater continental influence.
The Beqaa Valley floor contains no natural forest. Historical accounts describe the valley as grassland with scattered oak stands prior to agricultural development. Current vegetation consists almost entirely of cultivated crops, primarily grapes, wheat, and vegetables. Wild boar populations persist in the valley despite habitat loss.