Biomes

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Biomes are types of area on a planet, characterized by their terrain properties, climate, flora and fauna, diseases and special challenges. Each world tile has one particular biome.

Oceans and lakes appears as world tiles but are not playable biomes.

There are twelve playable biomes types in RimWorld, which can be divided into three categories: Warm, Hot and Cold.

The following is a simple summary of the biomes by difficulty, overall cold biomes are more challenging than their hot counterparts.

Warm Biomes

These biomes are rich in flora and fauna, and also have a slightly elevated rate of disease. They generally have year-round growing periods, or longer growing periods at the very least. Traveling speed is fast in normal forests and average in dense forests but slow in marshes and during cold seasons if they have one.

Temperate Forest

Forests of deciduous trees interspersed with fertile clearings. Many species of animals move around among the trees and on the plains.

Growing Season, Temperature, Travel and Disease

• Growing Season: From all year to 20/60 days.
• Average Temperature: 25 °C (77 °F) to 0 °C (32 °F).
• Temperature Variation: From 35 °C (95 °F) in summer to -25 °C (-13 °F) in winter.
• Roads and Rivers: Yes.
• Movement Difficulty: 1, but sometimes 3 due to winter.
• Forageability: 100%.
• Grazable: Only during growing season.
• Disease frequency: 1.2 per year.

Flora

Grass, Tall grass, Brambles, Dandelions, Bush, Oak tree, Poplar tree, Raspberry bush, Healroot.

Fauna

Hare, Squirrel, Rat, Deer, Wild boar, Turkey, Raccoon, Ibex, Muffalo, Buffalo, Alpaca, Boomalope, Boomrat, Tortoise, Gazelle, Megasloth, Rhinoceros, Grizzly bear, Timber wolf, Red fox, Cougar, Lynx, Warg.

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Temperate Swamp

Wetlands choked with vegetation and disease. Dense overgrowth makes it hard to move around, and clearing areas for building takes a long time. Much of the terrain is too marshy to support heavy structures.

A more wet version of the Temperate Forest. Like in all swamps, diseases are more common. The marshy soil will probably require bridges before constructing buildings and the terrain is really slow to travel, but this biome also has more fertile soil.

Growing Season, Temperature, Travel and Disease

• Growing Season: From all year to 20/60 days.
• Average Temperature: 25 °C (77 °F) to 0 °C (32 °F).
• Temperature Variation: From 35 °C (95 °F) in summer to -25 °C (-13 °F) in winter.
• Roads and Rivers: Yes.
• Movement Difficulty: 4, but sometimes 6 due to winter.
• Forageability: 75%.
• Grazable: Only during growing season.
• Disease frequency: 1.5 per year.

Flora

Tall grass, Chokevine, Bush, Willow tree, Cypress tree, Maple tree, Raspberry bush, Healroot.

Fauna

Hare, Squirrel, Rat, Tortoise, Deer, Wild boar, Turkey, Raccoon, Ibex, Muffalo, Alpaca, Boomalope, Boomrat, Megasloth, Rhinoceros, Grizzly bear, Timber wolf, Red fox, Cougar, Lynx, Warg.

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Tropical Rainforest

A thick, moist jungle, buzzing with animal life and infested with disease. Despite its visual beauty, this is a very dangerous biome. Choking overgrowth, aggressive animals, and constant sickness are why some explorers call this the "green hell".

Tropical Rainforests are famous for having many diseases, including Sleeping Sickness: a slow-progressing, long-lasting disease that is exclusive to the tropics. Many trees make it difficult to clear land and rapid plant growth makes it difficult to keep it clear.

Growing Season, Temperature, Travel and Disease

• Growing Season: From all year to 40/60 days.
• Average Temperature: 30 °C (86 °F) to 15 °C (59 °F).
• Temperature Variation: From 35 °C (95 °F) in summer to 0 °C (32 °F) in winter.
• Roads and Rivers: Yes.
• Movement Difficulty: 2, rarely 4 due to winter.
• Forageability: 100%.
• Grazable: Most of the time, during growing season.
• Disease frequency: 1.7 per year.

Flora

Grass, Tall grass, Low shrub, Alocasia, Cecropia tree, Palm tree, Bamboo tree, Teak tree, Bush, Clivia, Raspberry bush, Rafflesia.

Fauna

Rat, Monkey, Boomalope, Capybara, Cassowary, Tortoise, Chinchilla, Wild boar, Elephant, Rhinoceros, Alpaca, Cobra, Panther.

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Tropical Swamp

A plant-choked, steamy swamp seething with parasites and pathogens. Much of the land is too marshy to build on. Difficult movement, aggressive animals, and rampant disease make living here a nightmare.

A more wet version of the Tropical Rainforest. Like in all swamps diseases are more common. The marshy soil will probably require bridges before constructing buildings and the terrain is really slow to travel, but this biome also has more fertile soil. Diseases are even more constant here than in Tropical Rainforests, so making a proper hospital and having good doctors is a priority.

Growing Season, Temperature, Travel and Disease

• Growing Season: From all year to 40/60 days.
• Average Temperature: 30 °C (86 °F) to 15 °C (59 °F).
• Temperature Variation: From 35 °C (95 °F) in summer to 0 °C (32 °F) in winter.
• Roads and Rivers: Yes.
• Movement Difficulty: 4, rarely 6 due to winter.
• Forageability: 75%.
• Grazable: Most of the time, during growing season.
• Disease frequency: 2.0 per year.

Flora

Tall grass, Low shrub, Willow tree, Cypress tree, Maple tree, Chokevine, Alocasia, Bush, Clivia, Raspberry bush, Rafflesia.

Fauna

Rat, Monkey, Boomalope, Capybara, Cassowary, Tortoise, Chinchilla, Wild boar, Elephant, Rhinoceros, Alpaca, Cobra, Panther.

Hot Biomes

These biomes become progressively dry as they become more arid. Moderate amount of flora and fauna, which drops off as you pick a more extreme biome. Mostly year-round growing periods. Traveling in those biomes is usually fast and rarely slowed by cold seasons.

Arid shrubland

A dry region, but not dry enough to become a true desert. Open plains with grasses and bushes give way to scattered groves of trees. Plants are hardy and there is a moderate density of animals, but arable soil is hard to find.

Growing Season, Temperature, Travel and Disease

• Growing Season: From all year to 40/60 days.
• Average Temperature: 30 °C (86 °F) to 15 °C (59 °F).
• Temperature Variation: From 35 °C (95 °F) in summer to 0 °C (32 °F) in winter.
• Roads and Rivers: Yes.
• Movement Difficulty: 1, rarely 3 due to winter.
• Forageability: 50%.
• Grazable: Most of the time, during growing season.
• Disease frequency: 0.9 per year.

Flora

Grass, Dandelions, Bush, Pincushion cactus, Agave, Saguaro cactus, Drago tree, Raspberry bush.

Fauna

Alpaca, Boomalope, Boomrat, Cougar, Dromedary, Elephant, Emu, Fennec fox, Gazelle, Hare, Iguana, Megasloth, Muffalo, Ostrich, Rat, Rhinoceros.

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Desert

A very dry area which supports little life. There is very little arable land, and animal life is very sparse. Deserts can be hot, or quite cold.

With so few animals to hunt, growing crops is a priority on one of the few arable patches. The hot temperatures can cause problems for colonists and tamed animals. This biome has patches of soft sand which prevent building, but can be removed with moisture pumps.

Growing Season, Temperature, Travel and Disease

• Growing Season: From all year to 10/60 days.
• Average Temperature: 30 °C (86 °F) to 0 °C (32 °F).
• Temperature Variation: From 35 °C (95 °F) in summer to -25 °C (-13 °F) in winter.
• Roads and Rivers: Yes.
• Movement Difficulty: 1, but sometimes 3 due to winter.
• Forageability: 25%.
• Grazable: Only during growing season.
• Disease frequency: 0.7 per year.

Flora

Grass, Pincushion cactus, Saguaro cactus, Dandelions, Drago tree, Agave, Bush.

Fauna

Iguana, Dromedary, Boomalope, Ostrich, Emu, Gazelle, Cougar, Fennec fox.

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Extreme desert

An extremely hot, dry area, devoid of almost all life. Searing heat and a near total lack of arable land make it very difficult to survive here.

The hot temperatures can cause problems for colonists and tamed animals. Its warm enough for growing plants outdoors, but it has to be done in stony patches around hills and mountains. Even though potatoes grows better in stony soil, you need to plant rice first so you will not starve while waiting for potatoes. Strawberries are also a good idea since there is no wood for cooking. Later hydroponics can be used instead of ground. This biome has patches of soft sand which prevent building, but can be removed with moisture pumps. Animal migrations may occur, about once every other year.

Growing Season, Temperature, Travel and Disease

• Growing Season: From all year to 30/60 days.
• Average Temperature: 30 °C (86 °F) to 10 °C (50 °F).
• Temperature Variation: From 35 °C (95 °F) in summer to -5 °C (23 °F) in winter.
• Roads and Rivers: Yes.
• Movement Difficulty: 1, rarely 3 due to winter.
• Forageability: 0%.
• Grazable: Never.
• Disease frequency: 0.7 per year.

Flora

Grass, Saguaro cactus, Agave.

Fauna

Iguana, Dromedary, Fennec fox.

Cold Biomes

These biomes become progressively colder and hostile as they become more intense. Flora and fauna becomes more scarce as you pick a more extreme biome. Mostly seasonal growing periods but may go down to no growing period in more extreme biomes. Traveling in those biomes is usually slow due to marsh and cold seasons which can be very long.

Boreal Forest

Forests of coniferous trees. Despite the harsh winters, boreal forests sustain a diverse population of small and large animals, and have warm summers.

Growing Season, Temperature, Travel and Disease

• Growing Season: 30/60 days to 10/60 days.
• Average Temperature: 10 °C (50 °F) to -10 °C (14 °F).
• Temperature Variation: From 25 °C (77 °F) in summer to -35 °C (-31 °F) in winter.
• Roads and Rivers: Yes.
• Movement Difficulty: 1, but often 3 due to winter.
• Forageability: 75%.
• Grazable: Only during growing season.
• Disease frequency: 1.0 per year.

Flora

Grass, Brambles, Moss, Bush, Pine tree, Birch tree, Poplar tree, Raspberry bush, Healroot.

Fauna

Squirrel, Hare, Rat, Elk, Caribou, Muffalo, Wild boar, Ibex, Raccoon, Turkey, Deer, Megasloth, Red fox, Arctic fox, Grizzly bear, Timber wolf, Arctic wolf, Cougar, Lynx, Warg.

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Cold Bog

A wetland packed with trees and vines. Much of the marshy land here can't support heavy structures, moving around is slow due to choking vegetation. Disease is endemic in this dense, wet ecosystem.

A more wet version of the Boreal Forest. Like in all swamps, diseases are more common. The marshy soil will probably require bridges before constructing buildings and the terrain is really slow to travel, but this biome also has more fertile soil.

Growing Season, Temperature, Travel and Disease

• Growing Season: 20/60 days to 10/60 days.
• Average Temperature: 10 °C (50 °F) to -10 °C (14 °F).
• Temperature Variation: From 25 °C (77 °F) in summer to -35 °C (-31 °F) in winter.
• Roads and Rivers: Yes.
• Movement Difficulty: 4, but often 6 due to winter.
• Forageability: 50%.
• Grazable: Only during growing season.
• Disease frequency: 1.3 per year.

Flora

Chokevine, Tall grass, Moss, Bush, Astragalus, Willow tree, Cypress tree, Maple tree, Raspberry bush, Healroot.

Fauna

Squirrel, Hare, Rat, Elk, Caribou, Muffalo, Wild boar, Ibex, Raccoon, Turkey, Deer, Megasloth, Red fox, Arctic fox, Timber wolf, Arctic wolf, Cougar, Lynx, Warg, Polar bear, Grizzly bear.

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Tundra

These mostly-frozen plains bear almost no trees and little vegetation. There are a few small animals interspersed with large herds of migratory grazers and their predators. Animal migrations may occur once or twice per year.

Growing periods are generally very short or non-existent.

Growing Season, Temperature, Travel and Disease

• Growing Season: 20/60 days to never.
• Average Temperature: 0 °C (32 °F) to -20 °C (-4 °F).
• Temperature Variation: From 25 °C (77 °F) in summer to -50 °C (-58 °F) in winter.
• Roads and Rivers: Yes.
• Movement Difficulty: 1, but most of the time 3 due to winter.
• Forageability: 50%.
• Grazable: Only during growing season.
• Disease frequency: 0.8 per year.

Flora

Grass, Moss, Bush, Astragalus, Dandelions, Pine tree, Birch tree, Raspberry bush, Healroot.

Fauna

Hare, Snowhare, Caribou, Elk, Muffalo, Ibex, Megasloth, Arctic fox, Arctic wolf, Timber wolf, Lynx, Warg, Polar bear, Grizzly bear.

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Ice Sheet

Sheets of ice which can be kilometers thick. There is no soil for plants to grow in. The only animals here are migrating to somewhere else - or badly lost.

The only land possible to farm is stony patches around hills and mountains, but they need to be heated indoors and also have sun lamps. You will need to do hunting, trading and cannibalism until you get a heater and a sun lamp. Later, moisture pumps can create larger growable areas and hydroponics can be used instead of ground. Geothermal vents can be used for free heating. With so few animals here, any predators that roam in will become hungry soon and target your colonists and animals.

Growing Season, Temperature, Travel and Disease

• Growing Season: Never.
• Average Temperature: -20 °C (-4 °F) to -40 °C (-40 °F).
• Temperature Variation: From 10 °C (50 °F) in summer to -70 °C (-94 °F) in winter.
• Roads and Rivers: No.
• Movement Difficulty: 1.5, but most of the time 3.5 due to winter.
• Forageability: 0%.
• Grazable: Never.
• Disease frequency: 0.7 per year.

Flora

None.

Fauna

Snowhare, Muffalo, Polar bear, Arctic wolf, Arctic fox, Lynx, Megasloth.

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Sea Ice

Permanent ice sheets floating on water. There is no soil for plants to grow, no minerals to mine, and almost no animal life.

Sea Ice does not have ruins and geothermal vents. Deep drills do not work and moisture pumps will only generate more ice, which means it is impossible to grow anything on the ground. You will need to do hunting, trading and cannibalism until you get a heater, a sun lamp and a hydroponics basin. It is worth mentioning that Sea Ice was designed to not allow colony building, only to allow traveling in the area, even though it is possible.

Growing Season, Temperature, Travel and Disease

• Growing Season: Never.
• Average Temperature: -20 °C (-4 °F) to -30 °C (-22 °F).
• Temperature Variation: From 10 °C (50 °F) in summer to -60 °C (-76 °F) in winter.
• Roads and Rivers: No.
• Movement Difficulty: 1.5, but most of the time 3.5 due to winter.
• Forageability: 0%.
• Grazable: Never.
• Disease frequency: 0.7 per year.

Flora

None.

Fauna

Snowhare, Muffalo, Polar bear, Arctic wolf, Arctic fox.

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