Belgium occupies 30,528 square kilometers in Western Europe, sharing borders with the Netherlands to the north, Germany to the east, Luxembourg to the southeast, and France to the south and southwest. The North Sea forms the northwest boundary, providing 66.5 kilometers of coastline. The country divides administratively into three regions: Flanders in the north covering approximately 13,522 square kilometers, Wallonia in the south spanning roughly 16,844 square kilometers, and the Brussels-Capital Region at the center comprising 161.4 square kilometers. This structure creates a federation where regional governments exercise considerable autonomy over territorial matters including environmental policy and land use.
The terrain transitions through three distinct zones moving from northwest to southeast. The coastal plain extends approximately 15 to 20 kilometers inland from the North Sea, characterized by sandy beaches backed by dunes and polders—land reclaimed from the sea through drainage systems and protective dikes. Elevations in this zone rarely exceed 10 meters above sea level. The central plateau, covering most of Flanders and extending into parts of Wallonia, features gently rolling terrain between 50 and 200 meters elevation, predominantly agricultural with extensive wheat, sugar beet, and maize cultivation. The Ardennes occupies the southeastern portion of Wallonia, a forested highland plateau that forms the western extension of Germany's Eifel region. This zone contains Belgium's highest point, Signal de Botrange, which reaches 694 meters in the High Fens area near the German border. The Ardennes landscape consists of deeply incised river valleys, dense deciduous and coniferous forests, and exposed rock formations dating to the Paleozoic era.
The Scheldt River system drains most of Flanders, flowing 200 kilometers through Belgian territory from its source near Gouy in northern France, passing through Tournai, Ghent, and Antwerp before entering the Netherlands and reaching the North Sea through the Western Scheldt estuary. The Meuse River enters Belgium from France near Givet, flows 183 kilometers northward through Dinant, Namur, and Liège, then continues into the Netherlands. These rivers historically enabled Belgium's development as a trading hub, with Antwerp positioned on the Scheldt becoming one of Europe's largest ports. The Meuse carved the Mosan valley through the Ardennes, creating limestone cliffs that reach heights of 100 meters in sections near Dinant and Freyr. Smaller rivers include the Yser in West Flanders, deliberately flooded during World War I to halt German advances, and the Semois in the Ardennes, known for its meandering course through forested valleys.
Belgium's climate classification falls under temperate oceanic (Köppen Cfb), characterized by mild temperatures year-round, relatively high humidity, and precipitation distributed throughout all months. Atlantic maritime influences dominate, with prevailing westerly winds bringing moist air masses from the ocean. The coastal region experiences the most moderate conditions, with January mean temperatures around 3 to 4 degrees Celsius and July means of 17 to 18 degrees Celsius. Brussels records January averages near 3 degrees Celsius and July averages of 18 degrees Celsius, based on Royal Meteorological Institute data spanning 1991 to 2020. The Ardennes shows greater continentality, with January means dropping to 0 to 2 degrees Celsius and July means reaching 16 to 17 degrees Celsius. Absolute temperature extremes remain relatively narrow compared to continental climates: the national record high of 41.8 degrees Celsius occurred in Begijnendijk on June 25, 2019, while the record low of minus 30.1 degrees Celsius was recorded in Rochefort on January 20, 1940.
Annual precipitation across Belgium ranges from approximately 700 millimeters along the coast to 1,400 millimeters in the High Fens, the wettest area in the country. Brussels receives an average of 820 millimeters per year distributed across roughly 200 days with measurable precipitation. The coastal strip receives 750 to 800 millimeters annually, the central plateau 800 to 900 millimeters, and the Ardennes 900 to 1,400 millimeters depending on elevation and exposure. Precipitation patterns show slight peaks in summer months due to convective thunderstorms and again in November and December when Atlantic depressions intensify. Snow occurs throughout Belgium but accumulation varies significantly by region. The coastal zone sees an average of 10 to 15 days with snowfall per winter, though persistent snow cover remains rare. The Ardennes receives 40 to 60 days of snowfall annually, with snow cover lasting several weeks during typical winters at elevations above 500 meters. The High Fens can accumulate depths exceeding 50 centimeters during heavy snow events.
Seasonal transitions in Belgium remain gradual rather than abrupt. Spring from March through May brings increasing daylight and rising temperatures, with late frosts possible through mid-April in interior regions. May average temperatures reach 13 to 14 degrees Celsius in Brussels, with precipitation around 65 millimeters. Summer months from June through August rarely experience sustained heat, with temperatures exceeding 25 degrees Celsius on approximately 20 to 30 days per year in Brussels. Heatwaves—defined by the Royal Meteorological Institute as five consecutive days with maximum temperatures above 25 degrees Celsius including three days above 30 degrees Celsius—occur irregularly but showed increased frequency in the 2018 to 2020 period. Autumn from September through November sees declining temperatures and increasing rainfall, with November ranking among the wettest months at 75 to 80 millimeters in Brussels. December through February constitutes winter, characterized by gray skies, frequent drizzle, and occasional cold spells when continental high-pressure systems block Atlantic influences, bringing clear skies and temperatures below freezing.
Wind patterns reflect Belgium's exposure to Atlantic weather systems. The coast experiences average wind speeds of 5 to 6 meters per second, with storms producing gusts exceeding 30 meters per second several times per winter. Inland areas show lower average wind speeds around 3 to 4 meters per second, though the Ardennes ridges face exposure comparable to coastal zones during storm passages. The North Sea coast remains vulnerable to storm surges, particularly when northwesterly gales coincide with high spring tides. The 1953 North Sea flood affected the Belgian coast less severely than the Netherlands, but prompted construction of reinforced sea defenses including the raised promenade at Ostend and expanded dune preservation programs. Contemporary coastal defense strategy emphasizes natural dune systems supplemented by concrete seawalls in urban sections.
Belgium experiences approximately 1,500 to 1,600 hours of sunshine annually in most areas, among the lower figures in Western Europe due to frequent cloud cover. The coastal strip receives marginally more sunshine, around 1,650 hours, benefiting from occasional clearances when inland areas remain overcast. The Ardennes receives slightly less, around 1,400 to 1,500 hours, particularly in deeply incised valleys where topography limits direct sun exposure during winter months when the sun remains low on the horizon. July typically provides the most sunshine with 200 to 220 hours, while December averages only 45 to 50 hours. Persistent cloud cover creates a characteristic gray ambience during winter months, when several consecutive days may pass without meaningful direct sunlight.
Fog occurs with moderate frequency across Belgium, particularly in autumn and winter. The Scheldt and Meuse valleys experience radiation fog on calm, clear nights following daytime precipitation, when rapid surface cooling causes water vapor to condense. The Brussels-Capital Region records an average of 40 to 50 foggy days per year, defined as visibility below one kilometer. The High Fens experience hill fog when low cloud bases intersect elevated terrain, creating conditions where cloud and fog become indistinguishable. This occurs on 80 to 100 days annually at Signal de Botrange. Coastal fog forms less frequently than inland, though advection fog develops when warm air masses move over cooler North Sea waters during spring and early summer.