Minecraft Biome

Biome Definition

Biome definition files define biomes data-driven. Java Edition only.

Definition Format

Registry BIOME, data pack path worldgen/biome (files in data/<namespace>/worldgen/biome/; tags in tags/worldgen/biome/).

• has_precipitation (required) — whether the biome has precipitation.
• temperature (required) — temperature value.
• temperature_modifier (default none) — none or frozen (sets some areas to 0.2 before height adjustment).
• downfall (required) — affects plant colors (with temperature) but not actual precipitation.
• attributes — environment attribute map (position-dependent attributes only; duplicates → last value wins). See the environment-attributes skill.
• effects (required) — environmental effects (see below).
• carvers (required, may be empty) — carvers usable in the biome (tag/ID/inline/list).
• features (required, may be empty) — placed features; must have exactly 11 elements (one per decoration stage); each element is a feature tag/ID/list/inline.
• creature_spawn_probability (0–0.9999999, default 0.1) — initial animal spawn probability during worldgen.
• spawners (required, may be empty) — mob spawn entries per spawn category: {type (entity ID; "other"-category entities spawn pigs only), weight, minCount (>0), maxCount (>0)}.
• spawn_costs (required, may be empty) — spawn "potential" per entity: energyBudget (max energy a spawn can consume; smaller → fewer spawns) and charge (point-charge model; larger → fewer spawns).

Effects

• water_color (required) — RGB color.
• dry_foliage_color — dead-bush coloring.
• foliage_color — leaves/vines coloring.
• grass_color — grass block, grass, ferns, bushes, sugar cane, flower stems coloring.
• grass_color_modifier (default none) — none, dark_forest ((color & FEFEFE + 2634762) averaged), or swamp (noise-picked from 5011004/6975545).
• Unspecified plant colors use temperature/downfall color maps. Colors are affected by the "biome transition distance" video option.

Behavior

Biome definitions load once at server startup (/reload doesn't reload them — restart). In single-biome world presets every registered biome is selectable; its display name defaults to the namespace ID but can be set with the biome.<ns>.<path> localization key. Without a plains element in the BIOME registry the game refuses to load the world.

Feature Generation

The features list maps to the 11 decoration stages used by structure generation too:

1. RAW_GENERATION (End floating islands) 2. LAKES (lava lakes) 3. LOCAL_MODIFICATIONS (geodes, icebergs, basalt pillars) 4. UNDERGROUND_STRUCTURES (dungeons, fossils) 5. SURFACE_STRUCTURES (desert wells, blue ice, ice spikes) 6. STRONGHOLDS (unused) 7. UNDERGROUND_ORES (ore blobs) 8. UNDERGROUND_DECORATION (non-ore clusters, Nether ores) 9. FLUID_SPRINGS 10. VEGETAL_DECORATION (plants) 11. TOP_LAYER_MODIFICATION (frozen top layer).

Features beyond the 11 stages still place. Critical ordering rule: for all biomes in one dimension, each stage's features must have the SAME relative order (lists order by list order; tags by their values order; inline/IDs have no order). Violations crash the game at decoration with Feature order cycle found — the game does not pre-check, so verify manually.

Bone meal on grass in a biome can spawn any feature in the #can_spawn_from_bone_meal placed-feature tag whose placement succeeds there (vanilla uses this for biome-specific flowers).

Legacy Effects

Pre-1.19 effects (now replaced by environment attributes): fog_color, sky_color, water_fog_color, particle (options + probability), ambient_sound, additions_sound, mood_sound (tick_delay, block_search_extent, offset), music (weighted list of {data (sound, min_delay, max_delay, replace_current_music), weight}; empty = no music), music_volume (default 1).