From Dungeon Master's Guide and Players Handbook
Goal: Eventually make each weather condition hyperlinked so I can say that a thunderstorm strikes, click on the word thunderstorm, and know exactly what effects there will be.
Sometimes weather can play an important role in an adventure— rain can wash away tracks, a thunderstorm can force the adventurers to seek shelter, or a gale can delay their ship from sailing.
If your adventure involves spending a lot of time outdoors, create a random table to determine the weather conditions in a particular area. Local conditions have a dramatic effect on weather. High-altitude areas are often much colder than lowlands, for example. The presence of a mountain range can cause an area adjacent to the mountains where little precipitation falls.
Table 3–23: Random Weather is an appropriate weather table for general use, and you can use it as the basis for your own weather tables. Terms on that table are defined as follows.
Table 3–23: Random Weather
| d% | Weather | Cold Climate | Temperate Climate | Desert |
|---|---|---|---|---|
| 01–70 | Normal weather | Cold, calm | Normal for season | Hot, calm |
| 71–80 | Abnormal weather | Heat wave (01–30) or cold snap (31–100) | Heat wave (01–50) or cold snap (51–100) | Hot, windy |
| 81–90 | Inclement weather | Precipitation (snow) | Precipitation (normal for season) | Hot, windy |
| 91–99 | Storm | Snowstorm | Thunderstorm, snowstorm | Duststorm |
| 100 | Powerful storm | Blizzard | Windstorm, blizzard, hurricane, tornado | Downpour |
Weather Terms
Calm:Wind speeds are light (0 to 10 mph).
Cold: Between 0° and 40° Fahrenheit during the day, 10 to 20 degrees colder at night.
Cold Snap: Lowers temperature by –10° F.
Downpour:Treat as rain (see Precipitation, below), but conceals as fog. Can create floods (see above). A downpour lasts for 2d4 hours.
Heat Wave: Raises temperature by +10° F.
Hot: Between 85° and 110° Fahrenheit during the day, 10 to 20 degrees colder at night.
Moderate: Between 40° and 60° Fahrenheit during the day, 10 to 20 degrees colder at night.
Powerful Storm (Windstorm/Blizzard/Hurricane/Tornado): Wind speeds are over 50 mph (see Table 3–24: Wind Effects). In addition, blizzards are accompanied by heavy snow (1d3 feet), and hurricanes are accompanied by downpours (see above). Windstorms last for 1d6 hours. Blizzards last for 1d3 days. Hurricanes can last for up to a week, but their major impact on characters will come in a 24-to-48-hour period when the center of the storm moves through their area. Tornadoes are very short-lived (1d6×10 minutes), typically forming as part of a thunderstorm system.
Precipitation: Roll d% to determine whether the precipitation is fog (01–30), rain/snow (31–90), or sleet/hail (91–00). Snow and sleet occur only when the temperature is 30° Fahrenheit or below. Most precipitation lasts for 2d4 hours. By contrast, hail lasts for only 1d20 minutes but usually accompanies 1d4 hours of rain.
Storm (Duststorm/Snowstorm/Thunderstorm): Wind speeds are severe (30 to 50 mph) and visibility is cut by three-quarters. Storms last for 2d4–1 hours. See Storms, below, for more details.
Warm: Between 60° and 85° Fahrenheit during the day, 10 to 20 degrees colder at night.
Windy: Wind speeds are moderate to strong (10 to 30 mph); see Table 3–24
Rain, Snow, Sleet, and Hail
Bad weather frequently slows or halts travel and makes it virtually impossible to navigate from one spot to another. Torrential downpours and blizzards obscure vision as effectively as a dense fog.
Most precipitation is rain, but in cold conditions it can manifest as snow, sleet, or hail. Precipitation of any kind followed by a cold snap in which the temperature dips from above freezing to 30° F or below may produce ice (see Cold Dangers).
Rain: Rain reduces visibility ranges by half, resulting in a –4 penalty on Spot and Search checks. It has the same effect on flames, ranged weapon attacks, and Listen checks as severe wind.
Snow: Falling snow has the same effects on visibility, ranged weapon attacks, and skill checks as rain, and it costs 2 squares of movement to enter a snow-covered square. A day of snowfall leaves 1d6 inches of snow on the ground.
Heavy Snow: Heavy snow has the same effects as normal snowfall, but also restricts visibility as fog does (see Fog, below). A day of heavy snow leaves 1d4 feet of snow on the ground, and it costs 4 squares of movement to enter a square covered with heavy snow.
Heavy snow accompanied by strong or severe winds may result in snowdrifts 1d4×5 feet deep, especially in and around objects big enough to deflect the wind—a cabin or a large tent, for instance.
There is a 10% chance that a heavy snowfall is accompanied by lightning (see Thunderstorm, below).
Snow has the same effect on flames as moderate wind (see the following page).
Sleet: Essentially frozen rain, sleet has the same effect as rain while falling (except that its chance to extinguish protected flames is 75%) and the same effect as snow once on the ground.
Hail: Hail does not reduce visibility, but the sound of falling hail makes Listen checks more difficult (–4 penalty). Sometimes (5% chance) hail can become large enough to deal 1 point of lethal damage (per storm) to anything in the open. Once on the ground, hail has the same effect on movement as snow.
Storms
The combined effects of precipitation (or dust) and wind that accompany all storms reduce visibility ranges by three quarters, imposing a –8 penalty on Spot, Search, and Listen checks. Storms make ranged weapon attacks impossible, except for those using siege weapons, which have a –4 penalty on attack rolls. They automatically extinguish candles, torches, and similar unprotected flames. They cause protected flames, such as those of lanterns, to dance wildly and have a 50% chance to extinguish these lights. See Table 3–24: Wind Effects for possible consequences to creatures caught outside without shelter during such a storm. Storms are divided into the following three types.
Duststorm (CR 3): These desert storms differ from other storms in that they have no precipitation. Instead, a duststorm blows fine grains of sand that obscure vision, smother unprotected flames, and can even choke protected flames (50% chance). Most duststorms are accompanied by severe winds and leave behind a deposit of 1d6 inches of sand. However, there
is a 10% chance for a greater duststorm to be accompanied by windstorm-magnitude winds (see Table 3–24: Wind Effects).These greater duststorms deal 1d3 points of nonlethal damage each round to anyone caught out in the open without shelter and also pose a choking hazard (see Drowning, page 304—except that a character with a scarf or similar protection across her mouth and nose does not begin to choke until after a number of rounds equal to 10 × her Constitution score). Greater duststorms leave 2d3–1 feet of fine sand in their wake.
Snowstorm: In addition to the wind and precipitation common to other storms, snowstorms leave 1d6 inches of snow on the ground afterward.
Thunderstorm: In addition to wind and precipitation (usually rain, but sometimes also hail), thunderstorms are accompanied by lightning that can pose a hazard to characters without proper shelter (especially those in metal armor). As a rule of thumb, assume one bolt per minute for a 1-hour period at the center of the storm. Each bolt causes electricity damage equal to 1d10 eight-sided dice. One in ten thunderstorms is accompanied by a tornado.
Powerful Storms:
Very high winds and torrential precipitation reduce visibility to zero, making Spot, Search, and Listen checks and all ranged weapon attacks impossible. Unprotected flames are automatically extinguished, and protected flames have a 75% chance of being doused. Creatures caught in the area must make a DC 20 Fortitude save or face the effects based on the size of the creature (see Table 3–24). Powerful storms are divided into the following four types.
Windstorm: While accompanied by little or no precipitation, windstorms can cause considerable damage simply through the force of their wind.
Blizzard: The combination of high winds, heavy snow (typically 1d3 feet), and bitter cold (see Cold Dangers) make blizzards deadly for all who are unprepared for them.
Hurricane: In addition to very high winds and heavy rain, hurricanes are accompanied by floods. Most adventuring activity is impossible under such conditions.
Tornado: One in ten thunderstorms is accompanied by a tornado.
Floods
In many wilderness areas, river floods are a common occurrence. In spring, an enormous snowmelt can engorge the streams and rivers it feeds. Other catastrophic events such as massive rainstorms or the destruction of a dam can create floods as well. During a flood, rivers become wider, deeper, and swifter. Assume that a river rises by 1d10+10 feet during the spring flood, and its width increases by a factor of 1d4×50%. Fords may disappear for days, bridges may be swept away, and even ferries might not be able to manage the crossing of a flooded river.
A river in flood makes Swim checks one category harder (calm water becomes rough, and rough water becomes stormy). Rivers also become 50% swifter.
Fog
Whether in the form of a low-lying cloud or a mist rising from the ground, fog obscures all sight, including darkvision, beyond 5 feet. Creatures 5 feet away have concealment (attacks by or against them have a 20% miss chance).
Winds
The wind can create a stinging spray of sand or dust, fan a large fire, heel over a small boat, and blow gases or vapors away. If powerful enough, it can even knock characters down (see Table 3–24: Wind Effects), interfere with ranged attacks, or impose penalties on some skill checks.
Light Wind: A gentle breeze, having little or no game effect.
Moderate Wind: A steady wind with a 50% chance of extinguishing small, unprotected flames, such as candles.
Strong Wind: Gusts that automatically extinguish unprotected flames (candles, torches, and the like). Such gusts impose a –2 penalty on ranged attack rolls and on Listen checks.
Severe Wind: In addition to automatically extinguishing any unprotected flames, winds of this magnitude cause protected flames (such as those of lanterns) to dance wildly and have a 50% chance of extinguishing these lights. Ranged weapon attacks and Listen checks are at a –4 penalty. This is the velocity of wind produced by a gust of wind spell.
Windstorm: Powerful enough to bring down branches if not whole trees, windstorms automatically extinguish unprotected flames and have a 75% chance of blowing out protected flames, such as those of lanterns. Ranged weapon attacks are impossible, and even siege weapons have a –4 penalty on attack rolls. Listen checks are at a –8 penalty due to the howling of the wind.
Hurricane-Force Wind: All flames are extinguished. Ranged attacks are impossible (except with siege weapons, which have a –8 penalty on attack rolls). Listen checks are impossible: All characters can hear is the roaring of the wind. Hurricane-force winds often fell trees.
Tornado (CR 10): All flames are extinguished. All ranged attacks are impossible (even with siege weapons), as are Listen checks. Instead of being blown away (see Table 3–24: Wind Effects), characters in close proximity to a tornado who fail their Fortitude saves are sucked toward the tornado. Those who come in contact with the actual funnel cloud are picked up and whirled around for 1d10 rounds, taking 6d6 points of damage per round, before being violently expelled (falling damage may apply). While a tornado’s rotational speed can be as great as 300 mph, the funnel itself moves forward at an average of 30 mph (roughly 250 feet per round). A tornado uproots trees, destroys buildings, and causes other similar forms of major destruction.
Table 3–24: Wind Effects
| Wind Force | Wind Speed | Ranged/ Normal and Siege Weapon Attack Penalty | Creature Size | Wind Effect on Creature | Fort Save DC |
|---|---|---|---|---|---|
| Light | 0 -10 mph | 0 / 0 | Any | None | 0 |
| Moderate | 11-20 mph | 0 / 0 | Any | None | 9 |
| Strong | 21- 30 mph | -2/ 0 | Tiny or Smaller | Knocked Down | 10 |
| / | Small or Larger | None | 10 | ||
| Severe | 31- 50 mph | -4/ 0 | Tiny | Blown Away | 15 |
| / | Small | Knocked Down | 15 | ||
| / | Medium | Checked | 15 | ||
| Windstorm | 51- 74 mph | Impossible/–4 | Small or smaller | Blown Away | 18 |
| / | Medium | Knocked Down | 18 | ||
| / | Large or Huge | Checked | 18 | ||
| / | Gargantuan or Colossal | None | 18 | ||
| Hurricane | 75- 174 mph | Impossible/–8 | Medium or smaller | Blown Away | 20 |
| / | Large | Knocked Down | 20 | ||
| / | Huge | Checked | 20 | ||
| / | Gargantuan or Colossal | None | 20 | ||
| Tornado | 175- 300 mph | Impossible/Impossible | Tiny | Blown Away | 30 |
| / | Huge | Knocked Down | 30 | ||
| / | Gargantuan or Colossal | Checked | 30 | ||
1 The siege weapon category includes ballista and catapult attacks as well as boulders tossed by giants.
2 Flying or airborne creatures are treated as one size category smaller than their actual size, so an airborne Gargantuan dragon is treated as Huge for purposes of wind effects.
Checked: Creatures are unable to move forward against the force of the wind. Flying creatures are blown back 1d6×5 feet.
Knocked Down: Creatures are knocked prone by the force of the wind. Flying creatures are instead blown back 1d6×10 feet.
Blown Away: Creatures on the ground are knocked prone and rolled 1d4×10 feet, taking 1d4 points of nonlethal damage per 10 feet. Flying creatures are blown back 2d6×10 feet and take 2d6 points of nonlethal damage due to battering and buffeting.
THE ENVIRONMENT
Characters crossing the burning desert face heatstroke and dehydration. Plunging into the murky depths raises the risk of drowning and even decompression. Adventurers spend a lot of time in the most dismal, dangerous, and generally unpleasant places imaginable. If the monsters and the villains don’t kill them, the environment itself might. This section details hazards the player characters face from the physical world around them. Some of these hazards are specific to certain environments (the perils of severe heat almost never apply in an area of cold mountains, for instance), while others are threats that could come into play in any environment (such as acid effects or starvation and thirst).
COLD DANGERS
The prickly fingers of icy death have robbed many an adventurer of her life. Prolonged exposure to cold temperatures and harsh weather can wear down a character who isn’t protected against the climate. Hypothermia, frostbite, and exhaustion can quickly kill in bad weather. The best defense against cold and exposure is to get under cover and keep warm.
Cold and exposure deal nonlethal damage to the victim. This nonlethal damage cannot be recovered until the character gets out of the cold and warms up again. Once a character is rendered unconscious through the accumulation of nonlethal damage, the cold and exposure begins to deal lethal damage at the same rate.
An unprotected character in cold weather (below 40° F) must make a Fortitude save each hour (DC 15, + 1 per previous check) or take 1d6 points of nonlethal damage. A character who has the Survival skill may receive a bonus on this saving throw and may be able to apply this bonus to other characters as well (see the skill description, page 83 of the Player’s Handbook).
In conditions of severe cold or exposure (below 0° F), an unprotected character must make a Fortitude save once every 10 minutes (DC 15, +1 per previous check), taking 1d6 points of nonlethal damage on each failed save. A character who has the Survival skill may receive a bonus on this saving throw and may be able to apply this bonus to other characters as well (see the skill description, page 83 of the Player’s Handbook). Characters wearing winter clothing only need check once per hour for cold and exposure damage.
A character who takes any nonlethal damage from cold or exposure is beset by frostbite or hypothermia (treat her as fatigued; see page 301). These penalties end when the character recovers the nonlethal damage she took from the cold and exposure.
Extreme cold (below –20° F) deals 1d6 points of lethal damage per minute (no save). In addition, a character must make a Fortitude save (DC 15, +1 per previous check) or take 1d4 points of nonlethal damage. Those wearing metal armor or coming into contact with very cold metal are affected as if by a chill metal spell.
Ice Effects
Characters walking on ice must spend 2 squares of movement to enter a square covered by ice, and the DC for Balance and Tumble checks increases by +5. Characters in prolonged contact with ice may run the risk of taking damage from severe cold (see above).
HEAT DANGERS
The hot desert sun can be as deadly an enemy as a hostile tribe of orcs. Prolonged exposure to hot temperatures can quickly wear down a character, and heatstroke can be deadly. Heat deals nonlethal damage that cannot be recovered until the character gets cooled off (reaches shade, survives until nightfall, gets doused in water, is targeted by endure elements, and so forth). Once rendered unconscious through the accumulation of nonlethal damage, the character begins to take lethal damage at the same rate.
A character in very hot conditions (above 90° F) must make a Fortitude saving throw each hour (DC 15, +1 for each previous check) or take 1d4 points of nonlethal damage. Characters wearing heavy clothing or armor of any sort take a –4 penalty on their saves. A character with the Survival skill may receive a bonus on this saving throw and may be able to apply this bonus to other characters as well (see the skill description, page 83 of the Player’s Handbook). Characters reduced to unconsciousness begin taking lethal damage (1d4 points per hour).
In severe heat (above 110° F), a character must make a Fortitude save once every 10 minutes (DC 15, +1 for each previous check) or take 1d4 points of nonlethal damage. Characters wearing heavy clothing or armor of any sort take a –4 penalty on their saves. A character with the Survival skill may receive a bonus on this saving throw and may be able to apply this bonus to other characters as well. Characters reduced to unconsciousness begin taking lethal damage (1d4 points per each 10-minute period).
A character who takes any nonlethal damage from heat exposure now suffers from heatstroke and is fatigued. These penalties end when the character recovers the nonlethal damage she took from the heat.
Extreme heat (air temperature over 140° F, fire, boiling water, lava) deals lethal damage. Breathing air in these temperatures deals 1d6 points of damage per minute (no save). In addition, a character must make a Fortitude save every 5 minutes (DC 15, +1 per previous check) or take 1d4 points of nonlethal damage. Those wearing heavy clothing or any sort of armor take a –4 penalty on their saves. In addition, those wearing metal armor or coming into contact with very hot metal are affected as if by a heat metal spell.
Boiling water deals 1d6 points of scalding damage, unless the character is fully immersed, in which case it deals 10d6 points of damage per round of exposure.
Catching on Fire
Characters exposed to burning oil, bonfires, and noninstantaneous magic fires such as a wall of fire might find their clothes, hair, or equipment on fire. Spells such as fireball or flame strike don’t normally set a character on fire, since the heat and flame from these come and go in a flash. Characters at risk of catching fire are allowed a DC 15 Reflex save to avoid this fate. If a character’s clothes or hair catch fire, he takes 1d6 points of damage immediately. In each subsequent round, the burning character must make another Reflex saving throw. Failure means he takes another 1d6 points of damage that round. Success means that the fire has gone out. (That is, once he succeeds on his saving throw, he’s no longer on fire.)
A character on fire may automatically extinguish the flames by jumping into enough water to douse himself. If no body of water is at hand, rolling on the ground or smothering the fire with cloaks or the like permits the character another save with a +4 bonus.
Those unlucky enough to have their clothes or equipment catch fire must make DC 15 Reflex saves for each item. Flammable items that fail take the same amount of damage as the character.
Lava Effects
Lava or magma deals 2d6 points of damage per round of exposure, except in the case of total immersion (such as when a character falls into the crater of an active volcano), which deals 20d6 points of damage per round.
Damage from magma continues for 1d3 rounds after exposure ceases, but this additional damage is only half of that dealt during actual contact (that is, 1d6 or 10d6 points per round). An immunity or resistance to fire serves as an immunity to lava or magma. However, a creature immune to fire might still drown if completely immersed in lava (see Drowning, below).
SMOKE EFFECTS
A character who breathes heavy smoke must make a Fortitude save each round (DC 15, +1 per previous check) or spend that round choking and coughing. A character who chokes for 2 consecutive rounds takes 1d6 points of nonlethal damage.
Smoke obscures vision, giving concealment (20% miss chance) to characters within it.
WATER DANGERS
Historically, waterways were one of the most important modes of travel and communication within and between countries. On the other hand, characters on foot will find that lakes, rivers, and streams often block their travels in the wilderness. What’s more, underground streams, cisterns, sewers, and moats are all part of the dungeon environment.
Water presents adventurers with five general problems. First, it’s an obstacle that can block their movement. Second, characters in the water face the danger of drowning or losing gear. Third, a character caught in fast-moving water can be swept away from the rest of his party and battered or killed by rapids and waterfalls. Fourth, really deep water deals damage from the great pressure it exerts. Finally, exposure to cold water can be dangerous, afflicting characters with hypothermia.
The skills most commonly used in dealing with water as an obstacle are Swim and Profession (sailor). Unfortunately, not every character who gets into the water has these skills. Any character can wade in relatively calm water that isn’t over his head, no check required (hence the importance of fords). Similarly, swimming in calm water only requires skill checks with a DC of 10. Trained swimmers can just take 10. (Remember, however,that armor or heavy gear makes any attempt at swimming much more difficult. See the Swim skill description, page 84 of the Player’s Handbook.)
By contrast, fast-moving water is much more dangerous. On a successful DC 15 Swim check or a DC 15 Strength check, it deals 1d3 points of nonlethal damage per round (1d6 points of lethal damage if flowing over rocks and cascades). On a failed check, the character must make another check that round to avoid going under.
Very deep water is not only generally pitch black, posing a navigational hazard, but worse, it deals water pressure damage of 1d6 points per minute for every 100 feet the character is below the surface. A successful Fortitude save (DC 15, +1 for each previous check) means the diver takes no damage in that minute. Very cold water deals 1d6 points of nonlethal damage from hypothermia per minute of exposure.
Drowning
Any character can hold her breath for a number of rounds equal to twice her Constitution score. After this period of time, the character must make a DC 10 Constitution check every round in order to continue holding her breath. Each round, the DC increases by 1.
When the character finally fails her Constitution check, she begins to drown. In the first round, she falls unconscious (0 hp). In the following round, she drops to –1 hit points and is dying. In the third round, she drowns.
It is possible to drown in substances other than water, such as sand, quicksand, fine dust, and silos full of grain.
Supernatural/Magical Weather
Acid Rain
Acid Rain (CR 2): Acid rain deals 1d3 points of acid damage (no save) each round to anyone caught out in the open without shelter.
Rain reduces visibility by half, imposing a -4 penalty on Spot and Search checks. It also imposes a -4 penalty on Listen checks and ranged weapon attacks.
Rain automatically extinguishes candles, torches, and similar unprotected flames. It causes protected flames, such as those of lanterns, to dance wildly and has a 50% chance to extinguish these lights.
Prismatic Rain
Prismatic Rain: Prismatic rain falls in brilliant, rainbow-hued drops. Prismatic rain reduces visibility by three quarters, imposing a -8 penalty on Spot and Search checks. It also imposes a -4 penalty on Listen checks and ranged weapon attacks.
Rain automatically extinguishes candles, torches, and similar unprotected flames. It causes protected flames, such as those of lanterns, to dance wildly and has a 50% chance to extinguish these lights.
