Rain

A 31-second timelapse of a room darkening before rain.

A 30-second timelapse of increasingly heavy rain.

Rain is a timed environmental hazard deadly to Slugcat and all other creatures. It appears at the end of every cycle once the in-game timer has run out. It is preceded by the screen darkening, then by rumbling and screen-shake. These effects increase in intensity as the first drops of rain appear. The rain quickly increases in intensity until it is lethal, either crushing or drowning all creatures in affected rooms.

To avoid this hazard, the player must seek Shelter.

Variations

The arrival of rain has different effects depending on the room. In most outdoor rooms, rain directly impacts Slugcat's movement, most severely in areas with no overhead cover. Rain kills Slugcat faster depending on its strength. In most indoor rooms, rain causes flooding, which can drown Slugcat. In particular areas such as Five Pebbles, the upper limits of The Wall, Communications Array, Depths, and any Shelter, rain does not appear.

Instead of rain, The Leg and Underhang feature green sparks of electricity that bounce around at high velocity, stunning and killing Slugcat in a matter of seconds.

Both The Wall and Communications Array feature rooms where rain is permanently non-lethal, as a transition between higher, safe rooms and lower, lethal rooms.

In the minute before the end of a cycle in areas where rain occurs, the background darkens. At 30 seconds before the end of a cycle, vibrations of the oncoming rain can be seen and heard. From here, the rain most commonly increases steadily in strength from a drizzle to a lethal downpour over 45 seconds, after the last pip.

There is also a chance for the rain and associated vibrations to suddenly stop mid-buildup before becoming lethal. This type of rain lasts anywhere between 10 and 30 seconds with increasing numbers of single heavy droplets marking the end of the intermission. After this, the rain immediately jumps to its full strength and most indoor rooms begin flooding.

In Downpour, an additional rain pattern may occur. This rain alternates between no rain and heavy rain and lasts 25-65 seconds.

Cycles

Red is for Survivor and Hunter, Blue is for Monk, y axis it total number of minutes in cycle, x axis is random number between 0 (inclusive) and 1 (inclusive) that the game chooses

Each cycle in Rain World has a random duration, visible in the bottom left corner surrounding the karma symbol. The "pips" each represent 30 seconds, and each cycle can last a maximum of 26 pips (13 minutes) with an extra 20 seconds not shown in the timer. The minimum cycle length depends on the selected difficulty; Survivor and Hunter have a minimum cycle length of 13 pips (6 minutes and 30 seconds), while Monk has a higher minimum cycle length of 18 pips (9 minutes). Rivulet has the shortest minimum cycle length of only 5 pips (2 minutes and 30 seconds). The cycle timer can be seen at any time by viewing the map, and it flashes up automatically once half the cycle is gone.

Downpour-Exclusive Content

This section contains content exclusive to the Downpour DLC. This content is not available in the base game.

Shelter Failures

A flooded shelter.

Shelter failures have a small chance to occur at the start of a cycle. When a shelter failure occurs, the shelter Slugcat wakes up in is open and partially flooded, and it is raining outside; this is also known as a precycle. A flooded shelter cannot be used again until Slugcat has hibernated in a different shelter. Shelters with entrances at the bottom do not flood during precycles and can be hibernated in again immediately.

Slugcat surviving a torrent of precycle rain.

Precycle rain is lighter than end-of-cycle rain, is non-lethal, and dissipates after 2-5 minutes. The rain pushes creatures and objects against the ground until it lets up. It can cause death by knocking Slugcat into death pits and increases fall damage due to its force. If Slugcat is in a body of water, the rain forces them under the surface and may cause them to drown. The rain periodically slows, allowing for movement in roofless areas. The cycle timer is paused until the rain has fully stopped, making precycles longer than normal cycles. Creatures often attempt to retreat to their dens when the rain becomes more intense.

Shelter failures in The Leg and Underhang do not cause flooding, and precycle rain is replaced by the green electrical storms that are specific to these subregions. These precycle storms fade in and out intermittently and are non-lethal, but the sparks can knock Slugcat around when they become more intense.

During a precycle, most regions and rooms have special spawns, mainly aquatic creatures like Snails, Salamanders, Eel Lizards, Jetfish, and Monster Kelp.

Shelter failures can occur for any Slugcat except Saint, with a 2% chance in every region except for Five Pebbles, Metropolis, The Rot, and Looks to the Moon, where it does not happen at all. Shelter failures do not happen for Survivor or Monk prior to cycle 18. They are significantly more common for Rivulet, who has a 25% chance in every region except for Garbage Wastes, Shoreline, Shaded Citadel, and Pipeyard, which have a 40% chance. Rivulet's shelter failure chance drops to a flat 8% after the Rarefaction Cell has been obtained. Shelter failures occur every cycle for Inv except in Garbage Wastes and The Exterior.

Precycle Flooding

A room in Industrial Complex flooding.

Precycle flooding is a subfeature of the precycle mechanic, where the lower rooms of regions flood and drain with the force of the rain outside. This flooding has a 33% chance of happening in every region, except for The Exterior, Chimney Canopy, Sky Islands, and Submerged Superstructure, where it does not happen at all. The flooding disappears once the rain stops. Precycle flooding can be disabled in the More Slugcats Expansion Remix menu.

Day / Night Cycle

Within the uppermost rooms of The Wall, in most areas of Outer Expanse, and for the entire region of Metropolis and Luna, rain does not take effect. Instead, day transitions into night, changing the threat music and causing new creatures to spawn. The darkness brought on by the night cycle is similar to the darkness of Shaded Citadel.

• 

  The daylight stage

• 

  A sunset stage

• 

  Another sunset stage

• 

  The night stage

Blizzard

Rain is not present in Saint's campaign. Instead, snowfall gradually increases into a blizzard, decreasing all creatures' (except those immune to the cold) temperature until they hibernate or freeze. Saint shivers at low external temperatures, and their fur changes color depending on temperature; it starts green, fades slowly to white, followed by blue, and then a dull brown. Strawberry Lizards have a similar cosmetic effect where their color fades as snow falls on them.

Snow on the surface of water in Shoreline.

The water texture in exposed areas is altered to show snow on the surface.

Warmth

Some objects (including background objects) have a warming effect that can stave off the cold or even raise creatures' temperature. This effect occurs when they are swallowed as well as when held. Below is the full list of these objects:

Item/Background Object	Warmth
Lantern	1
Lantern Mouse	1.5 x charge (0-1)
Grenade	0.15
Cherrybomb	0.1
Steamer (on burst)	1 x Intensity
Steam pipe (on burst)	1 x Intensity
Light fixture	0.3
Karma gate	4-5

All types of explosions (such as those by Cherrybombs or Explosive Spears) set a fixed temperature. Artificer has a natural resistance to the cold, equal to one Lantern. When creatures are near each other, the temperature between them equalizes; if one is immune to the cold, it can be an infinite heat source.

Cycle Structure

At the beginning of a cycle, snow lightly falls over outdoor areas and all creatures are active. Outdoors, creatures' temperatures decrease quickly; Saint freezes in only a few minutes. Indoors, the decrease is slower and can be stopped entirely or reversed in the presence of warmth-providing objects.

As the blizzard approaches, temperature falls more rapidly and a fierce wind starts blowing. This wind makes it increasingly difficult to travel and can push creatures along the ground and off poles. When the blizzard is at full force, a single Lantern only keeps Saint at 3 pips of warmth indoors, even if they gain more from other sources. Being in the proximity of more Lanterns still increases Saint's temperature at a rate proportionate to their number until max, but the Lanterns required for this also increase as time goes on. Although it is cumbersome to carry multiple, having one swallowed allows for indoor travel almost indefinitely, with short bursts outdoors. However, spending too long without hibernating generally forces Saint to freeze, as the required lanterns far exceeds the number Saint can feasibly travel with.

Most creatures attempt to retreat to their dens; they prioritize this over other actions such as hunting. Some, however, are blizzard 'wanderers', and continue behaving normally, even as they start to freeze. Additionally, other creatures can be wanderers if marked with the {IgnoreCycle} tag. Wanderers exhibit the same signs as Saint when they are freezing: slowing down, shivering, falling over, and dropping items. If the cycle continues, they eventually die from the cold. Scavengers - especially those at Scavenger Tolls - typically last the longest as they tend to carry Lanterns and stick in large groups. Below is a list of all Wanderers:

Downpour-exclusive content ends here.

Trivia

• Bubble Weed can be used to prolong breath underwater while searching for Shelters in flooded underground rooms.
• Cycle time does not progress while passing through karma gates unless the rain has already started.
• The earliest concept of the rain as documented in the dev log

• In Looks to the Moon and Waterfront Facility, an alarm (labelled in the files as MOON_SIREN) plays when the rain approaches.