Lore of the Land

Toril is a large world, and Faerûn one of its largest continents. Thanks to diligent sages and scribes over centuries, the details and characteristics of many lands have been recorded. But in all that time, only a small part of Faerûn has been described in any detail.
To most folk who dwell in it, climate is a matter of harsh basics: when the seasons come, how the growing season (and therefore the available food supply) fares, and how severe the weather is the rest of the time. In general, the kingdoms of Faerûn produce more than enough food to feed their people and the various beasts that roam them. But localized shortages and the perils of lack of water, blistering heat, exposure, and freezing keep folk from complacency.
Climate
The lands of Faerûn encompass extremes from the frigid arctic to the steamy tropics. Few have conducted any real study of the continent's weather patterns. A farmer in the Heartlands knows only that winters are too long and cold, spring and fall too long and wet (with lingering frosts and too much mud), and the too-short summer is too hot. Perhaps the weather is better over the next hill.
Characteristics
Two chief characteristics describe a particular region's climate: its latitude and its precipitation. Of course, many local conditions can affect climate. High elevation, for example, has much the same effect as high latitude, so snow-capped mountains are not unheard of even in the tropics. Large bodies of water tend to moderate temperatures in the lands nearby. The ever-present strivings of the deities to bring about the kind of weather that pleases them is a factor of great importance in Faerûh. As often as not, it snows because Auril or Talos wants it to snow. Finally, great magical curses and spells can affect the weather over vast reaches - such as the Anauroch Desert.
The following survey of Faerûn begins at the Sword Coast and proceeds counterclockwise.
The Northwest
In its northernmost reaches, the Sword Coast is a forever frozen, wind-blasted waste that becomes the Endless Ice Sea overlying the continent as far east as one.can go. and still find land. A mountain range, the Spine of the World, holds back this polar ice cap from cloaking the Sword Coast North, but only onshore breezes make frozen Icewind Dale habitable at all - and that settlement lacks a growing season entirely.
South of the mountains is the crag- and lake-studded "Savage Frontier" of the North. These alpine valleys know only a short, fierce summer, and see icy water, chilling mists, and ice-capped mountains year-round. A little farther south, in the lower valley of the Dessarin, or the vales of the Gray Peaks, the land is rich and blessed with a long enough growing season to support great cities.
The northwest portion of Faerûn is generally well watered and humid, with heavy snowfalls in the winter and a great deal of rain in the spring and fall. Along the Sword Coast, folk exaggeratedly complain that it never stops raining.
As one travels south, the land warms until one can find dust, sand, and scorching heat around Scornubel and the southern reaches of the Anauroch Desert.
The Southwest
True temperate conditions hold sway from about the River Chionthar (Baldur's Gate) southward, and the land grows warmer and hotter until both true deserts and steamy temperatures are the rule in southern-most Tethyr and Calimshan. Sea breezes cool Nimbral, Lantan, and Tashalar, but volcanism makes the Lake of Steam area uncomfortable to most civilized inhabitants, and combines with latitude and warm sea-damp to make Chult and Mhair endless jungle steam baths.
The southwest, like the northwest, is very humid and receives a great deal of precipitation from the western seas. The cooling, moisture-holding properties of forests play a part in keeping Tethyr and the Border Kingdoms moderate in climate and pleasant places to live.
The Southeast
The Great Sea south of Halruaa is warm, and Rethild, Dambrath, Luiren, and the lands about the Golden Water are all warm to hot places of sweat, many insects, long summers, and short, stormy winters. The prevailing winds carry rainfall to the coastlands, but the mountain chains following the coastline (the Toadsquat and Gnollwatch mountains) create a rain shadow in the interior of this corner of Faerûn. The Shaar is an arid grassland that sometimes goes months without rain.
The great windblown plains of the Shaar, Raurin, and the Plains of Purple Dust are also far from the moderating effects of lakes and seas. Summers are extremely hot and dry, while winters can be perversely cold - the Shaar routinely experiences winter cold unknown in the southern reaches of the Sword Coast, more than a thousand miles to the north.
The Northeast
The icily aggressive cold of the Great Glacier affects most of the lands north and east of the Sea of Fallen Stars. This is an arid region, and forests do not flourish here. The Moonsea tends to be chilly year-round, and winds blowing south from the northern ice make Thar fiercely cold most of the year.
The Interior
If the Sea of Fallen Stars (also called the Inner Sea) did not exist, the center of Faerûn would most likely be a vast desert far from the rainfall and moderating temperatures of the coast. The Sea of Fallen Stars provides rainfall and moderate temperatures to the surrounding lands. Relatively shallow and affected in places by seabed volcanism, the Inner Sea warms the lands all around it, while at the same time keeping them damp (and therefore verdant, the Vilhon Reach in particular).
The winds and weather that. derive from the Inner Sea make Cormyr, Sembia, and the Dales quite pleasant places to live - despite cool mountain winds and harsh winters that often make the Wyvernwater and the coasts of the Moonsea, the Dragon Reach, and the Dragonmere freeze over.
The Oceans
The warmth felt by sailors on the eastern Great Sea speaks of the strength of warming ocean currents. They are the reason Zakhara enjoys moderate temperatures for a greater span of distance southward from the equator than the Sword Coast region does to the north, and also the reason why so much-of Kara-Tur and the known part of Maztica have warm climates.
Evermeet, the island kingdom of the elves far to the west of the Sword Coast, enjoys a far gentler climate than the Moonshaes, which are much closer to mainland Faerûn. A warm current sweeps northwest out of the Great Sea and curves past eastern Evermeet on its way toward the Icepeak and Icewind Dale, accounting for Evermeet's sunny climes.
Waterdeep lies slightly above the 45 degree north latitude line on Toril. The ocean's proximity moderates the more severe aspects of the northern climate, so rain falls as commonly as snow in fall and spring, changing roads to rivers of mud. Prevailing winds blow from the west to the east.
A vast southward-moving current, usually called the Southern Drift by sailors, lies immediately offshore from Waterdeep. This current is the tail end of a gigantic clockwise rotating current in the northern Trackless Sea between Maztica and Faerûn, encircling the Moonshaes and Evermeet. Interesting debris from across the sea sometimes floats past Waterdeep on the current.
Arctic winds often sweep down over Waterdeep in, late fall and winter, moving from the northwest to the southeast, carrying ferocious storms, snow, hail, and freezing rain. Icebergs are rarely seen here because of the warm offshore current, but ice often forms along the shore in winter and may clog Waterdeep's harbor. Icy roads are easier to travel over than muddy ones, which is why the spring thaw is regarded with glum favor by travelers, merchants, and soldiers.
Flora and Fauna
The vegetation and wildlife of an area are governed first and foremost by its weather. In northern, humid regions, evergreen forests are quite common. Temperate areas have deciduous forests. Toril is a large world, and Faerûn is only part of it - and even druids and rangers and explorers of long years in the wild do not claim to know all the kinds of forests or types of animals that may be found in Faerûn.
Trees And Shrubs
Travelers who have ventured into other planes and worlds claim that the same oak, ash, maple, chestnut, spruces, and pines among Faerûn's trees are also found in those distant places. Here follow a few of the most dramatic, plentiful, or useful trees and shrubs found only in Faerûn.
Blueleaf: Recognizable by the eerie, gleaming blue color of their many-pointed leaves, blueleafs (not "blueleaves") bend in winds or under ice rather than breaking, often forming snow tunnels that shelter winter travelers. Blueleafs grow close together in thick stands, reaching 40 feet in height but rarely attaining thick trunks.
Blueleaf wood is durable, and the sap and crushed leaves yield a vivid blue dye much favored in cloakmaking in the North. When burned, it yields beautiful leaping blue flames (prized in inns and taverns as "mood" illumination for tale-tellers and minstrels).
Blueleaf is found in humid temperate and subarctic latitudes north of Amn.
Helmthorn: A vinelike ground shrub that sometimes cloaks other bushes and dead trees, helmthorn has dark, waxy green leaves and bristling black thorns. As long as human hands, these sharp, durable thorns are often used as crude needles or dart points. Helmthorn berries are indigo in hue, edible (tart in flavor), and often harvested even when frozen or withered for use in winemaking.
Helmthorn is very hardy and grows throughout Fadriln, providing food for many.
Shadowtop: The soaring giants of Faerûnian forests, shadowtops can grow 2 feet a year and top out at 90 feet. A full-grown shadowtop flares out to a diameter of 10 feet or more at its base, its trunk surrounded by many pleatlike ridges. Shadowtops are named for the dense clusters of feathery leaves at the tops of their trunks. Shadowtop leaves are irregular in shape and have copper undersides and deep green upper surfaces.
Shadow-wood is fibrous and tough, but unsuitable for carving or structural work because under stress it splits down its length into splayed fibers. These fibers are valued in ropemaking (a few added to the twist improves the strength and durability of a completed coil) and burns slowly but cleanly, generating a very hot fire with little smoke. This makes it ideal for cooking.
Shadow-wood is much used in the making of magical staffs, rods, and wands.
Shadowtops are found in all humid areas across Faerûn.
Suth: Suth are graybark trees with olive-green leaves. They grow almost horizontally and then double back to angle in another direction. If a few suth trees grow together, their branches intertwine until they are inextricably entangled, forming a screen or wall barring passage to all things that can't fly over the tangled trees or scuttle under their lowest branches. Suth leaves are long, soft, and fluffy, but spike-ended.
Suth-wood is very hard and durable, so hard that it's difficult to work without the finest tools. Thin sheets of this wood retain astonishing strength for decades, and thus are favored for use in book covers. Suth is also the preferred wood for shields since it never shatters and doesn't catch fire if soaked in water before battle. A crushing blow might crack a suth-wood shield but won't cause it to fly apart.
The name of this tree may be a corruption of the word "south." Suth are found along the edges of the Shaar, in the woods of Chondath, and farther south in Faerûn.
Weirwood: Weir trees resemble oaks but have leaves that are brown (with a silver sheen) on their uppers and velvety black beneath. If undisturbed, weir trees grow into huge, many-branched forest giants. Weirwood won't ignite in normal (non-magical) fire and is resilient and durable. It's favored in the making of musical instruments because of the unmistakable warm, clear tone it imparts.
Weirwood can be used as a replacement for oak or holly in any spell. It grows throughout Faerûn but is very rare. Most trees are now found deep in large forests and actively protected by dryads, treants, druids, and rangers.
Zalantar: Often called blackwood in the North because of its jet-black wood and bark, the zalantar tree has a central root and eight or more trunks that branch out from the root at ground level like the splayed fingers of a hand. The trees may reach 60 feet in height, but are usually half that. Their leaves are white through beige. Zalantar wood is strong yet easily worked and sees much use in southern buildings and the making of wagons, litters, and wheels.
Southern wizards and sorcerers use durable and handsome zalantar wood almost exclusively in the making of rods, staffs, and wands.
This subtropical species is rarely seen north of the Shaar. It is plentiful along the shores of Chult and the southern coasts of Faerûn and seems to grow in any terrain short of mountainous.
Wild And Domestic Animals
Given the vast distances they travel, adventurers in Faerûn understand the value of a reliable mount. Those who seldom travel outside a city may care nothing about mounts, and instead think of avoiding, fighting, or eliminating guard beasts owned by others.
For humans, horses and mules are the most popular mounts for almost all purposes. In unusual situations such as aerial travel, Underdark travel, and extreme climates, folk favor griffons or pegasi, riding lizards, and camels in deserts or ghost rothé in frozen wastes.
Beasts of burden are usually valued for their strength, endurance, and temperament, with oxen at the head of the list and horses considered the most nimble (again, with adjustments for climate and nature of travel). Beyond that, most folk have little care for the wildlife around them except as it competes for their viands (wolves, foxes, and rats), offers them direct peril (poisonous snakes), or is easily snared or slain in the hunt for use on the table (rabbits, deer, grouse, and river fish that can be drag-netted or caught in a weir).
Dragons and other large predators that require great amounts of food often survey beasts around them very much as humans do - prizing herd animals grazing in the open as the easiest food to take.
The same endless wheel of eat-and-be-eaten governs life in Faerûn as in a dozen worlds. Folk who live close to the land (rangers, hunters, foragers, and farmers) know well that the little chipmunk-like rodent they call the berrygobbler is as important in the scheme of things as the wolf that eats the creature that ate the creature that devoured a luckless berrygobbler. They also know that dying berrygobblers signals some taint or fell magic or disease upon the land.
In the Heartlands, mice, rats, berrygobblers, rabbits, hares, raccoons, and squirrels are familiar scurriers underfoot. In Calimshan and Tashalar, the warmer climes see mice, rats, slinks (very swift black-furred berrygobblers), skradda (darting, sticky-tongued lizards that eat insects and small frogs), and sardrant (armadillo-like plant-chewers, slow-moving, shaggy, and semi-armored, with edible meat).
Fish leap out of the oceans and rivers: bluefin and silverfin, the brilliant, tiny, inedible silver jewelfish, and the splar (winged eels that can leap but not really fly).
The shaggy, buffalo-like rothé dwells in both hot and cold climes. The North has the ghost or snow rothé. The brown rothé ambles across the Heartlands and the South, becoming lighter in hue and less shaggy as latitudes become warmer. The deep rothé inhabits the Underdark.
Only foolish adventurers or city-dwellers ignore the lesser fauna of Faerûn. As the adventurer Steeleye once noted, "Rabbits fall easily into the stewpot, but downing, butchering, and cooking your dragon is a task that can take up your whole day."