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 shelter.

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 Five Pebbles, the upper limits of The Wall, Sky Islands's Communications Array, the lowest subregion of Subterranean (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.

While playing as the Saint, Rain is instead replaced with snow storms. While exposed to the snow, the Saint gradually gets colder, which is reflected by their change in color and with a meter under the food meter.

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, in which there is a residual downpour of rain, although not to a degree as severe as normal and with more oscillation, and one that 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 only remains potentially deadly within the first few minutes of the cycle, and will usually have to be waited out as wavering downpours and bullet rain will strike open areas, and rooms than can be flooded can start out fully flooded and only gradually drain once the rain calms down, which often leads to the player encountering Creatures that actively die to the rain or have drowned within a once flooded room. The most beneficial aspect of a pre-cycle is the total length of the cycle, which will often be higher than normal and will only start counting down once the rain has fully stopped, as it would appear within a normal cycle.

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.

Saint's Blizzard
During Saint's campaign, the normal cycle of the Rain is instead supplemented with the Blizzard mechanic, in which the Slugcat will have to maintain their body temperature under the increasing snowfall and wind. There is no cycle timer, and instead there is a variable amount of time before the blizzard will start and eventually increase in its severity, where the smaller gray pips under the player's Karma and food bar indicate their body heat, where at max the Saint will be fully green, and as this decreases the Slugcat slowly becomes more white and starts shivering. When all of the pips appear empty, the Slugcat will turn from a now pale blue into a sickly brown, losing motor function and occasionally losing consciousness, until they eventually can no longer move and freeze to death.

Tips

 * Bubble Weed can be used to prolong breath underwater while searching for shelter 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.