Rain

The Rain is a timed environmental hazard deadly to the player and all other creatures. It appears at the end of every cycle once the in-game timer has run out. It is preceded first by a darkening of the screen and 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.

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

In The Leg and The Underhang, the green sparks floating around the area accelerate and bounce around at high velocity, typically stunning and then killing the player in a matter of seconds.

Both The Wall and Communications Array feature rooms where the 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 thirty seconds before the end of a cycle, vibrations of the oncoming Rain can be felt 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 lasts for roughly 10 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.

Cycles
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 - and   have a minimum cycle length of 13 pips (6 minutes and 30 seconds), while   has a higher minimum cycle length of 18 pips (9 minutes). Of all the Slugcats, the has the shortest minimum cycle length of just five 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.

Pre-cycles
Pre-cycles are an event that has a small chance to occur at the start of a new cycle, at a 2% chance for most Slugcats. The cycle begins with the shelter already open and flooded, while outside there is a residual downpour of Rain. This Rain is not as heavy as end-of-cycle Rain, has more oscillation, and eventually dissipates with time, rather than building up to a climax. During a pre-cycle, most regions and rooms have special spawns, mainly including aquatic Creatures like s, s,, and more rarely s and. This Rain is still potentially deadly in the first few minutes of the cycle, and usually has to be waited out. Wavering downpours and bullet Rain strikes open areas, and some rooms may start flooded (if 'Pre-cycle flooding' is toggled on in the More Slugcats Remix menu) and only gradually drain once the Rain calms down. This often leads to the player encountering creatures that have died to the Rain or drowned in a once flooded room. The cycle timer only starts counting down once the Rain has fully stopped, so Pre-cycles give the player much more time than a normal cycle.

During a Pre-Cycle, Rain violently pours down on the region, similarly to how it does at the end of a cycle. This Rain is less lethal and does not kill the player outright if they are standing out in the open. Instead, the Rain bears down on any creature or item not under the cover of terrain or structures, slamming them against the ground until it lets up. It can cause death by knocking Slugcat into death pits, and because of how strong it forces Slugcat down, they can die via fall damage from shorter heights than usual. If Slugcat is in an area with deep bodies of water, the Rain forces them under the surface and may cause them to drown.

The Rain periodically slows down, allowing for movement in uncovered areas. An optional mechanic, pre-cycle flooding, may also be present if enabled. This causes certain indoor areas to be completely submerged in water, requiring the player to either find another route, attempt to swim through it, or wait the Rain out and for the rooms to gradually drain.

The cycle timer is paused during this event, and does not start until the Rain completely lets up and the color palette shifts to normal.

This event can occur for any Slugcat except the Saint. It is significantly more common for the Rivulet, and occurs every Cycle for ???.

Shelter Failures
Shelter Failures are a subfeature of the Pre-Cycle Mechanic, where in addition to the unique Creature spawns, increased Cycle length, and the downpour of Rain and room flooding, there is a small chance that the shelter that the player has hibernated within is already open and partially flooded at the start of a cycle, in which the shelter cannot be used again until the Slugcat has successfully hibernated within another still functional shelter. Regardless of where the shelter is, it is unavailable to be slept in until the following cycle.

Tips

 * Because the cycle timer is paused during a Pre-Cycle, the player can simply wait it out without risking dying to restricted time. However, shelter failures are relatively long, and if the player dies at any point, they have to wait again.
 * It may, however, be advantageous to do this in areas such as . Because Rain is absent from these areas, instead being replaced by electrical storms, the player is at risk of dying instantly upon exiting the Shelter and at any point they are outside.
 * Creatures often attempt to retreat to their dens as the Rain ramps up, even if where they are is sheltered; this can be utilized to pass certain areas safely.
 * Unless the player is confident in their handling of underwater controls and mechanics, it is best to avoid flooded areas or turn the option off entirely.

Day / Night Cycle
Within the uppermost rooms of The Wall, in most areas of, and for the entire Region of , deadly Rain does not take effect as in other high altitude areas. Instead, day transitions into night, changing the threat music and causing new creatures to spawn. The darkness brought on by the night cycle is intense, so carrying around a light source or utilizing the glow of a is recommended.

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 if the external temperature would normally lower theirs, and their fur changes color depending on temperature; it starts green, fades slowly to white, followed by blue, and then a dull brown. s have a similar cosmetic effect where their color fades as snow falls on them.

Some creatures have the {Winter} tag in Saint's campaign, which gives them an alternate appearance. Salamanders, Caramel Lizards and Eel Lizards do not have an alternate appearance. Otherwise, all in Saint's campaign have fur tufts on their heads. have a more faded palette and s have blue accents instead of their usual red.

The water texture in exposed areas is also 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: All types of explosions (such as those by Cherrybombs or Explosive Spears) set a fixed temperature. 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
There is no Pre-cycle chance in Saint's campaign. On a new 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 even push creatures along 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:

Tips

 * can be used to prolong breath underwater while searching for Shelters in flooded underground rooms.
 * Cycle time does not pass while passing through gates, unless the Rain cycle has already started.
 * Cycle time also does not pass during a Shelter Failure, and only starts to pass once the Rain stops.