Weather Rules
Everything presented is subject to change as the adventuring party discovers hidden secrets.
Temperature and Weather
These rules aren’t intended to apply to creatures native to the local climate. With rare exceptions, creatures native to any locale are adapted to the local weather. Mammals grow thick pelts to survive cold winters, etc.Weather Table
Clouds
Though they have no effect on the temperature, cloud coverage still changes some of the game.Clear Skies / Light Clouds
Clear skies, allowing bright light during day time and characters the ability to view the stars and moon at night. No modifiers are added to play.Heavy Clouds
The sky is blocked. High flying aerial creatures have total cover and outdoor light does not count as sunlight (for the purposes of sunlight sensitivity and similar traits). Checks using Navigation Tools to determine your location based on celestial observation are made with disadvantage.Wind
Wind can make temperatures feel much colder. On a hot day, the wind can feel welcome. On a cold day, it makes the cold that much worse.Moderate Wind
Winds at a speed between 13 and 31 mph move the weather one step toward cold temperatures.Strong Wind
Winds above 31 mph move the weather two steps toward cold temperatures. They also bestow disadvantage on ranged weapon attack rolls and Wisdom (Perception) checks that rely on hearing.They extinguish most open flames, disperse fog, and may affect other relevant conditions. Flying by non-magical means is impossible. Most flying creatures must land by the end of their turn or fall.
Depending on terrain, strong wind may also cause sand, snow, or dust to obscure vision, imposing disadvantage on Wisdom (Perception) checks to see.
Precipitation
Light Precipitation
Light rain, gentle snowfall, or similar conditions move the weather one step toward cold temperatures. It also gives disadvantage on Wisdom (Perception) checks to see at long distances.If you have wagons, your travel pace is slowed by half. If you attempt to take a long rest without cover, you must make a DC 12 Constitution saving throw to gain the benefits of that long rest.
Heavy Precipitation
Heavy rain, snow, or similar conditions move the weather two steps toward cold temperatures. Everything in the area of the precipitation is lightly obscured. Creatures have disadvantage on Wisdom (Perception) checks that rely on sight. Heavy rain or hail also imposes disadvantage on Wisdom (Perception) checks and immediately extinguishes open flames, such as campfires and torches.If you have wagons, your travel pace is slowed by half. If you attempt to take a long rest without shelter, you must make a DC 16 Constitution saving throw to gain the benefits of that long rest.
If heavy rain occurs two days in a row, wagon travel becomes impossible until one day without rain occurs.
May cause flooding.
Humidity
Low Humidity
Air is dry or not significantly humid. This has no effect on the weather.Moderate Humidity
Air is somewhat humid. This moves the weather one step away from comfortable.High Humidity
Air is steamy, foggy, or there is otherwise a lot of water hanging in the air. This moves the weather two steps away from comfortable.Equipment and Precautions
Creatures that are well-equipped to handle the temperature or who take precautions to protect themselves can often mitigate extreme temperatures.A creature must be using any of these for the vast majority of the time period leading up to a saving throw to benefit from it. You cannot travel 59 minutes, light up a fire, sit next to it for 1 minute, and it count.
Clothing and Armor
Clothing is humanoids’ first line of defense against the elements: Wearing warm clothing in the winter and cool clothing in the summer. For creatures wearing multiple types of clothing (such as cold weather gear over heavy armor), use whichever type of clothing is the warmest. For example: If a creature is wearing heavy armor and hot weather clothing, use the modifier for heavy armor.Cold-Weather Clothing
This clothing set includes heavy gloves, woolen stockings, insulated boots, thick jackets, fur-lined cloaks, scarves, etc. The base price for this is 10 gp. Wearing cold-weather clothing moves you two steps toward hot temperatures.Heavy Armor
Full plate and similar heavy armor include layers of chain mail and padded clothing, all of which can insulate the wearer. Bearing heavy armor moves you one step toward hot temperatures.Heavy Clothing
Cloaks, long clothing, multiple layers, etc. Wearing heavy clothing moves you one step toward hot temperatures.Light or No Clothing
Short sleeves, etc. Keep in mind that going unclothed or with lots of bare skin in hot temperatures can actually make things worse due to sun exposure. Please don’t read this article and die of heat stroke. Wearing light clothing or wearing nothing both move you one step toward cold temperatures.Hot-Weather Clothing
This clothing set is made of breathable materials, head coverings, and other garments built to protect from the sun while remaining breathable. Clothing wetted with cool liquid can also suffice, so long as the garment is wetted repeatedly. The base price for this clothing set is 15 gp. Wearing cold-weather clothing moves you two steps toward cold temperatures.Food and Drink
Warming Food and Drink
Consuming warm food and beverages like tea or hot soup can make cold temperatures feel more comfortable. However, these benefits aren’t as consistent as other countermeasures.Upon consuming any of the aforementioned in cold weather, you gain advantage on your next saving throw against cold temperatures. However, consuming any in hot weather bestows disadvantage on your next saving throw against hot weather.
Cooling Food & Drink
Iced beverages, frozen foods, and potentially spicy foods like peppers (they make you sweat without raising your body temperature) can make hot weather more tolerable.Upon consuming any of the aforementioned in hot weather, you gain advantage on your next saving throw against hot temperatures. However, consuming any in cold weather bestows disadvantage on your next saving throw against cold weather.
Environment
Direct Sun Exposure
Sun exposure can make temperatures feel warmer. In some cases, other sources of light can have similar effects. If a creature is exposed to the sun for the vast majority of any given time period, it moves one step toward hot temperatures.Shade
Taking frequent breaks to cool off in the shade can make hot temperatures much more manageable. This might mean sitting under a shady tree, or it might mean traveling in a litter with a shade over you. If a creature spends the vast majority of a given time period in the shade, it moves one step toward cold temperatures.Tools
Warming Apparatus
Any mechanism used to warm the user. A hot stone that radiates heat, a campfire, etc. Utilizing a warming apparatus moves you one or more steps toward hot temperatures. How many steps is up to the DM, but should be one if it's not very effective.Cooling Apparatus
Any mechanism used to cool the user. A device blowing cool mist, a creature fanning another creature, etc. Utilizing a cooling apparatus moves you one or more steps toward cold temperatures. How many steps is up to the DM, but should be one if it's not very effective.Natural Adaptations
Some creatures are native to extreme climates, but might not have actual damage resistance. Those creatures can more readily handle cold or hot temperatures than creatures not similarly adapted. This might include creatures with specific physical adaptations, but at the DM’s discretion, it might also include creatures who have spent a significant amount of time adapting to that climate.At the DM’s discretion, the creature treats all temperatures as one step colder or one step hotter depending on their adaptations. It might ignore the effects of humidity. The creature might ignore the effects of direct sun exposure.
Resistances and Immunities
Resistances or immunities, whether natural or conveyed by magic, can protect creatures from temperature extremes just as they protect creatures from damage.Cold Immunity
A creature with cold immunity suffers no negative effects from anything below comfortable temperatures.Cold Resistance
Creatures with cold resistance treats cold temperatures as 3 steps closer to comfortable.Fire Resistance
Creatures resistant to fire treat hot temperatures as 3 steps closer to comfortable.Fire Immunity
Creatures immune to fire ignore any negative effects from anything above comfortable temperatures.Putting it All Together
That was a lot. It feels like a lot to keep track of when it’s all listed out like it is above, but when you think about handling temperatures in real life it should all feel intuitive. Let’s look at some examples.Susan, a human, is visiting her friend Snek, the lizardfolk, at home in the local swamp. The swamp is moderately humid today, and it’s a hot summer day (the “Hot” temperature band). Susan often travels in heavy armor, but due to the weather, she instead wears light clothing. Even so, it’s still very hot, so Susan drinks plenty of water and takes frequent breaks to rest in the shade.
How does that all total up? We start with the “Hot” weather band. We go one step away from Comfortable due to the humidity (toward hot temperatures in this case), then one step toward cold temperatures due to Susan’s light clothing. That still puts Susan in the Hot weather band, so she’s going to make Constitution saves unless she takes additional measures. She remembers to drink plenty of water, so she won’t suffer disadvantage in any saves she makes, but she also takes breaks in the shade to cool off, reducing the effective temperature from Hot to Mildly Hot, which is uncomfortable but not problematic. Susan tells herself that she’ll buy some hot weather gear next time she plans a visit.
So how does Snek handle the situation? Snek grew up in the swamp, and lizardfolk, much like regular lizards, are cold-blooded and enjoy direct sunlight. That gives Snek several natural adaptations which the DM rules will mitigate the weather. The DM decides that Snek is accustomed to mild humidity, warm temperatures, and direct sunlight, so the DM will ignore the humidity, move Snek’s effective temperature band one step toward cold due to their comfort in warm temperatures, and ignore the detriments of direct sunlight. So on a Hot day, Snek experiences it as “Mildly Hot”. Snek decides to go without clothing (typical for lizardfolk), reducing the temperature band one step further to “Comfortable”. Snek is right at home.
Susan and Snek are later dragged into a Rime of the Frostmaiden campaign and are exposed to a great deal of cold weather. They find themselves in the middle of a blizzard on what was already a Severely Cold day. Icewind Dale is trapped under perpetual winter, so the limited sunlight isn’t helping. The DM rules that the wind is mild but the precipitation is heavy. Susan and Snek came prepared and they’re wearing cold-weather clothing.
Starting from the Severely Cold band, we adjust downward two bands for heavy precipitation, and one more band for mild wind, putting the weather below Incredibly Cold by one step. Susan and Snek are both wearing cold weather clothing, which raises their effective temperature by two steps back to Extremely Cold. They’re in a lot of trouble!
They won’t be able to light a fire, and there’s no cover nearby, so they both drink potions of cold resistance. Cold resistance raises their effective temperature two more steps to Mildly Cold. The DM then applies Snek’s adaptation to warm climates, which drops Snek back down to Cold. Snek, seeing that Ten Towns is exactly as bad as they were told, pulls out a thermos of warm soup (warming food and drink) and hopes for the best as he prepares for a series of Constitution saving throws unless the snow lets up or they find a place to take cover from the storm.
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