Arcane Weather: Master the Power of Magical Storms

by Michael Mearls, Dragon #308

Magic saturates many D&D campaign worlds. Wizards and sorcerers forge arcane energy into powerful spells, while clerics and druids channel the power of the gods. Any reasonably experienced fighter has an enchanted sword, a suit of magic armor and an array of potions. Even a prosperous innkeeper might have an everburning torch or two with which he can keep his front porch illuminated even in inclement weather.

In a world where magic is common-place, it stands to reason that arcane effects can occasionally spill over into the natural world. After all, magic is a force of nature that exists within the campaign world, not outside of it. As a natural force, magic normally lies unnoticed in the background until a spellcaster takes steps to call on its power and bind it to his purposes. In some cases, however, the line between the natural world and the magical forces it contains breaks down. When such an event occurs, mundane events acquire magical characteristics that transform them into dangerous, bizarre phenomena.

The results are all the more startling when magic affects a natural process such as weather patterns. An infusion of magical energy can transform an ordinary rainstorm into a roiling mass of arcane power accompanied by winds that carry howling, terrifying ghosts. Clouds infused with elemental fire can rain down massive bursts of flame and coat the countryside with ash.

Magical weather can introduce a new sense of wonder into your campaign world. It can also remind the players that magic is a dangerous force, not a mere tool to be bent and twisted as they wish. When incorporated into your adventures, magical weather can turn a mundane wilderness encounter into a deadly struggle or add another layer of danger to an urban campaign. A cyclone tinged with planar energies can provide as difficult and interesting a challenge as a many-headed hydra or a powerful lich who leads a legion of undead.

This article provides a method for incorporating magical weather effects into a D&D game. (The guidelines offered here work hand-in-hand with the rules for heat, freezing cold, wind, rain, and other weather conditions.) In addition, a new "weather wizard" prestige class called the aeromancer is introduced, along with several new feats that involve the recognition and manipulation of weather patterns.

Building Magical Storms

A magical storm is an unusual or violent weather pattern that exhibits one or more magical abilities. Some magical storms produce particular magical effects, such as a rain of frogs or a plague. Others affect spellcasting within their areas, often enhancing or inhibiting the casting of spells from certain schools or with certain descriptors. A magical storm also includes one or more mundane weather conditions. All these effects can be mixed or matched as you wish to create unique storms.

To build a magical storm, select a "base storm" (either mundane or magical) from the options presented in this article, or create your own. Then add one or more magical traits (see below), specifying the spell schools, descriptors, or specific spells to be affected by each. Finally, choose one or more mundane traits from the lists given for the base storm and the selected traits. You can also mix two or more magical storms together, if you like.

Magical storms involve bizarre tempests and other natural events fueled by magical or otherworldly power. Unless otherwise noted, each lasts 2d4-1 hours and covers an area of 3d6 square miles. The descriptions given below are merely starting points; you can modify them as desired to fit your campaign world.

Magic storms move at one eighth of their base wind speed in miles per hour. Magic storms with wind speeds less than 1 mile per hour or less are treated as stationary.

The Weather Statistics Block

A storm of any sort can be described with a short block of game statistics, similar to that of a monster or NPC, that summarizes its abilities and effects. The template given below provides an easy way to reference weather effects.

Storm Name/Type: Temperature; wind type (normal ranged attack penalty/siege missile penalty), Fort DC, Size [of creature affected]: effect [on those creatures]; precipitation (effects); special weather traits [included only if needed].

Below are a few examples of statistics blocks for mundane storms.

Blizzard: 10 degrees F; windstorm winds (impossible/-4 penalty, Fort DC 18, S or smaller: blown away, N: knocked down, L or H: checked); snow (-4 penalty on ranged attack rolls and Search and Spot checks, one-half movement).

Greater Dust Storm: 90 degrees F; windstorm winds (impossible/-4 penalty, Fort DC 18, S or smaller: blown away, N: knocked down, L or H: checked); none; wind-driven dust deals 1d3 points of subdual damage per round to anyone caught in the open and is a choking hazard (see the drowning rule) to a traveler whose mouth and nose are uncovered.

Thunderstorm: 80 degrees F; strong winds (-2 penalty/-, Fort DC 10, T or smaller: knocked down); rain (-4 penalty on ranged attack rolls and Listen, Search, and Spot checks).

Magical Storms

When an arcane storm rolls into an area, barely a hint of its true power is apparent to most observers, but wizards, sorcerers, and other arcane spellcasters can feel the oppressive weight of its fury. Clear, calm weather usually accompanies such a storm. The air smells faintly of ozone, sparks flare when metal strikes metal, and spellcasters hear a faint, droning buzz in their minds that rises and falls with the storm's strength.

Arcane Storm

An arcane storm tears apart magical energy, twisting it like a hurricane twists coastal buildings. This effect causes a spellcaster's power to fluctuate wildly. One moment, a mighty wizard's spells fizzle out in a flash of sparks. The next moment, a weakling apprentice unleashes a spell at a power level far beyond his capability. A successful Knowledge (arcana) check (DC 20) reveals the presence of an arcane storm.

Each time an arcane spellcaster tries to cast a spell while within the storm's area, his caster level either increases by 1d4 points or decreases by 1d4 points (50% chance for each). This alteration applies only to the casting of that spell; the character's caster level returns to normal immediately afterward. Should the character's caster level drop to zero or below, the spell is lost.

If desired, you can create an arcane storm that affects only divine magic or one that affects both arcane and divine magic. You can even create one that affects one or more spell schools, descriptors, specific spells, or some combination thereof.

Mundane Effects: Calm winds, clear skies, moderate temperature, any type of precipitation.

Divine Storm

A divine storm appears when a deity either enters the Material Plane or directly touches it in some manner. A deity can also dispatch a divine storm to aid supporters. The tremendous influx of divine magic warps and twists the atmosphere, producing a storm with hurricane winds and rain.

Each divine storm is infused with the essence of the deity that created it. Thus, such a storm has an alignment subtype - chaotic, evil, good, lawful, or some combination thereof - that matches an aspect of its creator's alignment. The alignment subtype determines the storm's effects, as given below.

Chaotic: Chaotic storms result when planar energies from strongly chaotic realms, such as Pandemonium, cross over to the Material Plane. These powerful thunderstorms feature multi-hued, ever-shifting clouds that produce rainfall, snow, and hail, as well as more unusual types of precipitation (frogs, chunks of wood, or other objects; see below). The kind of precipitation changes at seemingly random intervals. Every 2d6 minutes that the storm persists, roll d% and consult the table below to determine the nature of the precipitation.

In addition, a chaotic storm has a bizarre effect on anyone trapped within it. Each minute that a creature remains within a chaotic storm, it must succeed at a Fortitude save (DC 15) or turn into a randomly determined monster as though it were the target of a polymorph spell. To determine the creature's new form, roll on a random encounter chart (such as one of the encounters in Random Encounters. Regardless of the result, the affected creature must make a new saving throw against the polymorph effect each minute that it remains within the storm's area. The creature reverts to its original form when it leaves the area or when the storm ends.

Chaotic Storm Precipitation
51-60Small animals
91-100Reverse precipitation

Rain, Snow, Sleet, or Hail: See Weather.

Stones: Small rocks pummel the ground, dealing 1 point of subdual damage per minute to each creature caught in the open. Otherwise, treat this effect as hail.

Small Animals: Snails, crabs, rats, and other small creatures fall from the air. Upon hitting the ground, they split open and rapidly decay, creating a horrid stench that deals 1d4 points of Strength damage to every creature in the area that fails a Fortitude save (DC 15). The slime and blood from the creatures' broken bodies reduces movement by one-half. When the storm ends or passes from the area, ability scores damaged by this effect return to normal, and the remains of the tiny creatures disappear.

Bones: Human bones tumble from the sky, forming small piles that assemble themselves into skeletons, animate, and attack. Each minute that this effect continues, there is a 25% chance that 1d4 skeletons attack any creature or group of creatures within the area. Once the storm ends or passes from the area, the skeletons clatter to the ground in pieces.

Blood: Blood falls from the sky like rain, staining the land a crimson red. Every creature caught in this rain must make a Fortitude save (DC 15) or be nauseated for 1d4 rounds.

Feathers: A great, dense cloud of feathers fills the air, hindering sight and muffling sounds. The feathers impose a -4 penalty on all Listen, Search, and Spot checks made in the storm's area. Visibility is limited to 5 feet, and all targets within that range have one-half concealment.

Reverse Precipitation: Water rises from puddles and lakes, and snow soars into the sky, leaving the ground bare and clear.

Mundane Effects: Any. In addition to randomizing the precipitation, the chaotic storm's winds and severity vary wildly from minute to minute. Every 2d6 minutes, roll 1d100 to determine the wind's current speed in miles per hour.

Evil: These storms form thick, dark clouds that blot out the sun and render the day dark as night. The howling wails and moans of undead creatures echo from the clouds.

Each nonevil living creature in the storm's area with 3 or fewer Hit Dice must make a successful Will save (DC 13) or become shaken (-2 morale penalty on attack rolls, checks, and saves). An evil storm's dark energy also has a sustaining effect on undead: Every undead creature in the storm's area gains turn resistance +2 if it did not already have that ability, or increases its existing turn resistance by +2.

Mundane Effects: Thick clouds, rain or snow, any sort of wind.

Good: This divine storm manifests as a bright, warm day. The sun shines even at night, helping to drive evil and undead creatures into their dark homes underground. The air has a slight scent of cinnamon, which serves to hearten good creatures and give them the strength and confidence to stand strong in battle.

While in the area of this storm, each evil creature with 3 or fewer Hit Dice must make a successful Will save (DC 13) or suffer a -1 morale penalty on attack rolls, checks, and saves. Each good creature within the storm's area gains a +1 morale bonus on attack rolls, checks, and saves,

Mundane Effects: Clear sky, light wind.

Lawful: Lawful deities send these storms to regions their followers wish to pacify or conquer. A lawful storm manifests as a set of perfectly formed, square blocks of cloud that create an evenly spaced pattern in the sky. The creatures and objects in areas covered by this storm quickly fall into predictable, orderly patterns. Herds of cattle march in precise formations, while a sheet of paper torn to pieces and tossed into the air falls into a perfectly arranged pile.

A lawful divine storm might lack the pyrotechnics of a good or evil storm, but it represents a much more sinister danger. Every minute as a free action, any lawful creature in the storm's area may issue a one-word order that functions like a command spell (as the spell as if cast by a 1st-level caster), except that it can be directed at one or more specified targets within 20 feet. The order affects up to the commanding creature's Hit Dice in targets. If creatures in excess of this limit are targeted, those with fewer Hit Dice are affected first. Lawful creatures are immune to this effect every other potentially affected creature must make a Will save (DC 11 + commanding creature's Charisma modifier) to resist. This effect ends when the storm does.

Mundane Effects: A lawful storm usually exhibits one single set of weather conditions, which remains in force for the full duration of the storm. Common conditions include snow (which blots out the environment and gives the terrain a uniform color and shape) and strong, steady winds.

Fire Storm

In a fire storm, thick, red clouds filled with the seething power of elemental fire float through the sky. Thundering explosions echo within these clouds, scattering a light rain of ashes over the land. The temperature rapidly soars above 100 degrees, vaporizing light snow and small puddles of water in the space of 10 minutes.

Any spell with the fire descriptor cast within the area of this storm receives the benefit of the Empower Spell feat, or the Maximize Spell feat if it is already empowered. An elemental with the fire subtype gains temporary hit points equal to its Hit Dice in a fire storm, and any Reflex save made to avoid catching fire or to extinguish flames suffers a -2 circumstance penalty.

Mundane Effects: Strong or faster winds, hail (chunks of coal), dust storms, windstorms, tornadoes.

Hell Storm

Spawned from the very depths of Hell, this fiery cyclone carries with it a host of imps and lemures, plus a few more powerful devils. These outsiders dance and caper in the hell storm's winds, spreading destruction and death as they please. A hell storm's black clouds gather the sun's light and transform it into a rust-red hue that bathes the land below. A thick stench of brimstone and sulfur overwhelms all other odors, while the heat soars to more than 100 degrees, even in the depths of winter.

Water simmers in the heat of this storm, dealing 1d4 points of subdual damage per hour to each aquatic creature in contact with it. For each hour spent within a hell storm, there is a 25% chance to encounter a group of devils with an Encounter Level appropriate for the creature or group.

Mundane Effects: Howling winds that carry the laughter of devils and range from moderate to fast speeds, rain, hail, tornadoes.

Murderous Heat

This subtle, deadly form of magical weather slowly wears down the nerves and will of its victims, transforming them into murderous psychopaths over the course of a few days. A murderous heat is a hot, humid weather system infested with dark magic. Creatures exposed to this heat slowly become more irritable and ill-tempered. Eventually, this seething rage explodes into violence. A simple jest or a jostle that normally would pass without a word now sparks a fist fight.

Murderous heat lasts 2d4+1 days. For each day that it persists, every creature within its area must attempt a Will save (DC 10 + the number of days the heat has persisted). Failure indicates that the creature resorts to violence the next time it faces a stressful situation or a conflict of any sort. For example, a merchant might lunge at the throat of a customer who attempts to barter down prices, or a city guard might beat a man senseless merely for setting up his market stall too far out in the street. Such a bout of violence lasts for 2d6 rounds, after which the victim regains his or her senses. This violence is a mind-affecting, Enchantment effect.

Mundane Effects: Light wind, searing heat, high humidity.

Plague Winds

The gods of plague and contagion delight in spreading sickness across the world. In regions where an epidemic has scythed through the population, the survivors whisper of a foul-smelling, tainted wind that flowed through the region, carrying death wherever it blew. A plague wind can range from a fearsome storm that saturates an area with disease to a light breeze that slowly sows the seeds of sickness.

Plague winds are rarely easy to identify. Although they occasionally carry a scent of rotten eggs or spread a green haze across the sky, the lords of disease prefer subtler weapons that strike their victims unaware.

A plague wind lasts 2d6+1 days. Select a disease from the diseases table. Each day that the winds persist, every humanoid in the area is exposed to that disease and must attempt a Fortitude saving throw at the given DC to resist its effects. A +2 circumstance bonus applies to this save because of the diffuse nature of the disease.

Mundane Effects: Any wind.

Psychic Storm

This powerful mote of psychic energy disrupts the minds of creatures within its area. A psychic storm is like a pit in the psionic landscape - it draws mental energy into it, saps the minds of living creatures, and disrupts their ability to think clearly. To all outward appearances, whatever mundane weather pattern previously existed continues as normal; wind, rain, snow, and heat are unaffected by the storm's development. Instead, its signs can be found in the actions of those who must endure the mental tempest.

The first noticeable sign of a psychic storm occurs 24 hours after the storm starts. All creatures in the area are plagued by vague but terrible nightmares that disrupt their sleep. A wave of forgetfulness, sloppy work, absentmindedness and general incompetence follows the first night of this effect and persists throughout the storm. Every creature in the affected area takes a -2 competence penalty on all skill checks because of fitful sleep and inability to focus on the tasks at hand.

After 1d4 days of this effect, the symptoms begin to worsen, Psionic abilities fail to function 25% of the time, an the action used to activate such an ability is wasted if the attempt fails.

The storm reaches its peak 2d6 days after it begins. A spellcaster or a psionic creature must make a Concentration check (DC 20 + spell level or power level) to successfully cast a spell or use a psionic ability. The same check is required for the use of spell-like abilities. Furthermore, every creature in the storm's area must make a successful Will save (DC 15) or suffer a crushing headache that imposes a -2 circumstance penalty on attack rolls, checks, and saving throws. The -2 competence penalty previously applied to skill checks also remains in effect. These effects persist for 1d4 days.

Once the peak period is over, the storm takes another 1d4 days to dissipate. During this time, only the initial -2 competence penalty on skill checks remains. All penalties disappear when the psychic storm ends.

Mundane Effects: Any.

Magical Weather Traits

The following traits affect the level of magical energy in a storm system or area. Each description includes a list of mundane weather conditions that might accompany the trait. Magical traits can be applied to both mundane and magical base storms.

Deadening Air

Sometimes the ambient magic in an area drains away, making spellcasting a trying, difficult task, The weather reflects this lack of energy with utterly still air, moderate temperatures, and cloudy skies.

Select one or more schools of magic or spell descriptors (such as electricity, fire, fear, or sonic), or some combination of both. A spellcaster attempting to use a spell that falls into any of the selected categories must make a successful Spellcraft check (DC 10 + spell level + 1d10) to cast it; otherwise the spell fails and is lost. (If desired, you may specify the variable adjustment portion of the Spellcraft DC rather than rolling it to reflect the specific level of magic in the area.) Unless otherwise stated, a deadening air effect lasts as long as the storm with which it is associated.

You can also specify particular spells to be affected, in addition to or instead of schools of magic and spell descriptors, if the logic of the situation requires it. Thus, a deadening air effect can be custom-designed to match the overriding nature of an area, or to dovetail with its history and the legends that surround it. For example, a temple to the god of the sea might have a permanent deadening air effect that makes it difficult to cast fire spells. Likewise, any spell that creates water should be difficult to cast in a magically created desert.

A successful Survival or Spellcraft check (DC to) detects the presence of deadening air. A second successful Spellcraft check (DC 30) identifies the spell school or descriptor affected.

Mundane Effects: Calm winds, overcast skies, moderate temperature.

Magical Flux

Just as a storm causes the air to roil in fury, so too can it interfere with the natural flow of magic. A magical flux augments the power of certain spells when they are cast within its area.

Select one or more schools of magic or spell descriptors (such as fire, fear, or sonic), or some combination of both, plus one metamagic feat, Any spell that falls into any of the selected categories automatically gains the benefit of the metamagic feat you have chosen when cast within the storm's area. The caster need not have access to the feat to gain this benefit. If desired, a caster can negate the metamagic effect by making a successful Spellcraft check (DC 15) upon casting the spell. Unless otherwise stated, a magical flux effect lasts as long as the storm with which it is associated.

As with the deadening air trait, you can also specify particular spells to be affected, in addition to or instead of schools of magic and spell descriptors.

A successful Survival or Spellcraft check (DC 10) detects the presence of a magical flux. A second successful Spellcraft check (DC 30) identifies the spell school or descriptor that the flux affects and the metamagic feat that it applies to spells.

Mundane Effects: Winds, rain, hail, or any other stormy condition.


A wizard who practices magic in an area with lower than normal levels of magical energy might find that her spells are much stronger when she enters a region of normal magic. A frontier ranger might learn to predict a plague wind after surviving the effects of one. The new feats presented below reflect the benefits of exposure to or study of arcane weather.

Predicting Weather

Characters can use the Knowledge (nature) skill to predict the weather. Although weather has little impact on most adventures, a trek through an arctic tundra or a scorching desert can go from difficult to fatal as the weather changes in severity, and knowing a day ahead of time that a magical storm is due in the area can mean success or failure from some heroes.

Once per day, you may attempt a Knowledge check (DC 10) to predict the weather for the next day. A character can predict weather patterns farther than one day in the future, but each day beyond the first increases the DC by 5. For example, predicting the weather for the day after tomorrow requires a successful Knowledge (nature) check (DC 1). Predicting a magical storm is much more difficult than predicting normal weather. Any time that a character attempts to predict the weather for a day during which a magical storm will occur must exceed the day's normal DC by 10 in order to also accurately predict the magical storm's occurrence, If a character's Knowledge Nature check exceeds the day's normal DC by less than 10, the character knows the general weather for the day but does not know of the impending magical storm. If a character fails to meet the required DC, the prediction attempt fails and the character does not learn anything about the day's weather. Any time a character fails a Knowledge (nature) check to predict normal weather by more than 5, the character receives false information about the day's weather.

Magic in the Realms