Exploration

Senses and Light

The most fundamental tasks of adventuring—noticing danger, finding hidden objects, hitting an enemy in combat, and targeting a spell, to name just a few—rely heavily on a character's ability to see. Darkness and other effects that obscure vision can prove a significant hindrance.

Obscured Areas

A given area might be Lightly or Heavily Obscured. In a Lightly Obscured area, such as dim light, patchy fog, or moderate foliage, creatures have disadvantage on Wisdom (Perception) checks that rely on sight.
A Heavily Obscured area—such as darkness, opaque fog, or dense foliage—blocks vision entirely. A creature effectively suffers from the blinded condition when trying to see something in that area.

Light

The presence or absence of light in an environment creates three categories of illumination: bright light, dim light, and darkness.
Bright light lets most creatures see normally. Even gloomy days provide bright light, as do torches, lanterns, fires, and other sources of illumination within a specific radius.
Dim light, also called shadows, creates a lightly obscured area. An area of dim light is usually a boundary between a source of bright light, such as a torch, and surrounding darkness. The soft light of twilight and dawn also counts as dim light. A particularly brilliant full moon might bathe the land in dim light.
Darkness creates a Heavily Obscured area. Characters face darkness outdoors at night (even most moonlit nights), within the confines of an unlit dungeon or a subterranean vault, or in an area of magical darkness.

Special Senses

Some creatures might have special senses that allow them to perceive the world around them differently. Certain items, class features and spells can also allow a character to gain these abilities. The followin special senses are defined in the rules glossary:

Blindsight
Darkvision

Tremorsense
Truesight

Interacting with Objects

A character's interaction with objects in an environment is often simple to resolve in the game. The player tells the GM that his or her character is doing something, such as moving a lever, and the GM describes what, if anything, happens.

Defining an Object

For the purposes of the game's rules, an object is a discrete, inanimate item like a sword, door, table, window, or rock. It isn't a building, or a vehicle, which are composed of multiple objects. The remains of creatures are considered objects, but have some unique rules associated with them.

Destroying Objects

Characters can also damage objects with their weapons and spells. Objects are immune to poison and psychic damage, but otherwise they can be affected by physical and magical attacks much like creatures can. The GM determines an object's Armor Class and hit points, and might decide that certain objects have resistance or immunity to certain kinds of attacks. (It's hard to cut a rope with a club, for example.) Objects always fail Strength and Dexterity saving throws, and they are immune to effects that require other saves. When an object drops to 0 hit points, it breaks.
A character can also attempt a Strength check to break an object. The GM sets the DC for any such check.

Travel

Characters often go on journeys that cover great distances and takes hours, days, or weeks. Using the fact -paced time scale of an encounter would be arduous for tracking this kind of travel. Instead, the GM adjusts the time scale depending on the context of the situation at hand.
Within a building or dungeon, movement happens on a scale of minutes. It might take about a minute to creep down a long hallway, another minute to check for traps on the door at the end of the hall, and a good ten minutes to search the chamber beyond for anything interesting or valuable.
In a city or wilderness, a scale of hours is often more appropriate. A party eager to reach the lonely tower at the heart of the forest hurry across those fifteen miles in just under four hours’ time.
For long journeys, a scale of days works best. Following the road from Valderon to Arandesh, the party spends four uneventful days before an orc ambush interrupts their journey.

Travel Pace

Every creature has a speed, which is the distance in feet that the creature can walk in a round. This number assumes short bursts of energetic movement in the midst of highly time sensitive situations.
When a creature or group of creatures is traveling for more than a minute, they can move at the speed shown on the Travel Pace table. The table states how far a party of creatures can move in a period of time based on their base walking speed. When determining your group's travel speed, always round up to the nearest increment of 10.
For example, a dwarf with a base walking speed of 25 can keep up with his human companions (base walking speed of 30) easily enough by walking at a slightly brisker pace.

Travel Pace Table

For each addition increment of 10 feet to a creature's speed, the creature can cover an additional 100 feet per minute, and an additional mile per hour.
The distance a creature can reasonably cover in a day is limited by their fatigue threshold, which is defined in the rules glossary.

Difficult Terrain

The pace and distances given in the Travel Pace table assume relatively simple terrain: roads, open plains, or clear dungeon corridors. When traveling through difficult terrain, you can cover only half the normal distance listed.

Vehicles

Characters in wagons, carriages, or other land vehicles choose a pace as normal. Characters in a waterborne vessel are limited to the speed of the vessel, and they don’t suffer penalties for a fast pace or gain benefits from a slow pace. Depending on the vessel and the size of the crew, ships might be able to travel for up to 24 hours per day.

Marching Order

When traveling or exploring, you will establish a marching order.
A marching order makes it easier to determine which characters are affected by traps, which ones can spot hidden enemies, and which ones are the closest to those enemies when a fight breaks out. You can change your marching order at any time outside of an encounter.

Activities While Traveling

While traveling, you can engage certain activities while moving, the Traveling Activities table lists the main traveling activities. If you're traveling for an hour or less, you can change your chosen activity at the end of each minute. If you're traveling for more than an hour, you can change your chosen activity at the end of each hour.

Traveling Activity	Description	Base Speed Change
Avoid Detection	You move stealthily (See the "Stealth" skill), attempting to hide if the terrain allows for concealment.	10 ft. Slower
Forage	You attempt to gather food and water (See the "Wilderness" skill).	10 ft. Slower
Hustle	You push yourself to move at a brisk pace. While moving at this pace, you suffer a -5 penalty to your passive Wisdom (Perception) rating to notice hidden threats or points of interest.	10 ft. Faster

Traps and Hazards

Any non-sentient challenges imposed on you by the environment is either a trap or a hazard.
Traps are intentional interventions put in place to hinder or harm. Traps tend to be hidden, and their danger is apparent only when they are perceived or unwittingly activated.
Hazards are rarely hidden, and their danger is typically out in the open, but it may require knowledge or deduction to recognize what precisely that danger is.
The description for each Trap or Hazard contains the following:

• Level. Indicates how dangerous the trap or hazard is.
• Detection. The DC of the Wisdom (Perception) check required to detect the trap or hazard.
• Recognition. The DC of any other ability check that might reveal something about the trap or hazard.
• Trigger. A description of the events that trigger the activation of the trap or hazard.
• Effect. A description of what happens after the trap or hazard is triggered.
• Countermeasures. A description of what is required to disable or overcome the trap or hazard.

Traps and Hazards are primarily used by the GM, but certain features allow players to make use of some of them as well.

Diseases

Traveling through muck, or a plague-ridden town can expose you to biological hazards in the form of diseases.
When the GM determines that you've been exposed to a disease, you'll make a Fortitude Save to avoid contracting it. The DC of the Saving Throw varies based on the type of disease and the severity of your exposure to it. On a failed save, you become Afflicted with the disease. Whenever you become afflicted with a disease, you start with a number indicating the Stage of the disease. A disease can have any number of Stages, and usually becomes progressively worse as you advance through these them.
While afflicted in this way, you might suffer a variety of detrimental effects based on the Stage of your disease, described in the disease's description. Each disease description also contains details on how the disease is transmitted, how often you save to prevent the disease progressing, and the DC of the save.
The GM has access to these disease description but they need not reveal all the elements of a disease when a PC first contracts it. Instead, the GM might reveal more about the disease as it affects the PC.

Weather

At the start of each day, the GM can roll on one of the seasonal weather tables below, or choose the weather for the day. Weather may not always be relevant to what's going on in the game, so the GM Different regions might have modifiers for the weather in that area, making certain weather events more or less likely. Some regions may exclude certain seasons altogether. For example, there are no true summers in the frigid lands of Vhoreen.

Weather by Season

Winter	Fall	Spring	Summer

Weather Conditions

The weather conditions referenced in the Weather by Season table are explained below:

Clear Skies or Light Clouds

Clear and bright sunlight during daytime, with a view of the moon and stars at night unobstructed by cloud cover. You might experience Dim Light outdoors at nighttime during Clear Skies or Light Clouds during a full moon.

Heavy Clouds

The sky is obscured by clouds. Creatures flying above 6000 feet have Total Cover, and Wisdom (Wilderness) or Wisdom (Navigator's Tools) checks have Disadvantage.

Rain

All the effects of Heavy Clouds apply to Rain. In addition, Mounts pulling Drawn Vehicles have their Speed halved while traveling in the rain. The benefits of a Short or Long Rest are halved if you rest in rain without cover.

Heavy Rain

All the effects of Rain and Heavy Clouds apply to Heavy Rain. In addition, while outdoors during Heavy Rain, you are Fire Tolerant (-2), Lightning Sensitive (+4) and Cold Sensitive (+4).

Freezing Cold

Severely cold temperatures below 0 degree Fahrenheit. The benefits of a Short or Long Rest are halved if you rest without cover or warmth. In addition, while outdoors during Freezing Cold, you are Cold Sensitive (+4).

Snow

All the effects of Heavy Clouds and Freezing Cold apply to Snow. In addition, all creatures moving on land have their Speed halved while traveling in the snow.

Scorching Heat

Blistering temperatures above 100 degrees Fahrenheit. A creature exposed to the heat has their dehydration limit halved. In addition, while outdoors during Freezing Cold, you are Fire Sensitive (+2) and Cold Tolerant (-2).

High Winds

High Winds imposes disadvantage on ranged weapon attack rolls and Wisdom (Perception) checks to listen. A strong wind also extinguishes open flames, disperses fog, and makes flying by nonmagical means nearly impossible. A flying creature in a strong wind must land at the end of its turn or fall.

Thunderstorm

All the effects of Rain, High Winds and Heavy Clouds apply to a Thunderstorm. While outdoors all creatures more than 20 feet from you are Lightly Obscured.

Blizzard

All the effects or Snow, High Winds, and Freezing Cold apply to a Blizzard.
While outdoors all creatures more than 20 feet from you are Lightly Obscured.
At the end of every hour spent in a Blizzard, make a DC 12 Fortitude Save. On a failure, you take 3d4 cold damage and gain one level of exhaustion. You have advantage on the Save if wearing Heavy Clothes.