Snowfall

Snowfall is a type of weather that occurs occasionally in Minecraft.

Behavior
Snowfall is a temporary, biome specific occurrence that can happen randomly at any time in snowy biomes. In most lush biomes, snowfall occur at altitude above 255, while in cold biomes its specific to several biomes. In stone shore, mountains and variants, snowfall can only occur at layer 90 and above, in taiga, giant tree taiga and variants (except giant spruce taiga), snowfall can occur only at layer 120 and above, or 150 and above while in giant spruce taiga., within the Overworld. In hot/dry biomes, and in other dimensions, it does not snow at all.

The average snowfall lasts 0.5 – 1 Minecraft day, and there is a 0.5 to 7.5 day delay between snowstorms. Snowstorms have a small chance to worsen into thunderstorms.

Snowstorms can be skipped entirely with the use of a bed.

Effects


Snowstorms darken the world, causing the light from the sun to decrease by 3, bringing it to light level 12 in full daylight. Moonlight, however, is not reduced, and remains at light level 4. The sky itself darkens (even in biomes where it does not snow), to the point where celestial bodies (the sun, moon, and stars) are no longer visible. The clouds darken from white to a light gray, although clouds themselves do not precipitate. Although the sun is not visible during snowfall, the glow associated with sunrise and sunset is still visible.

As it snows, snow layers regenerate over all non-transparent blocks. $$, these snow layers accumulate and grow over time.

Snow particles
Falling snowflake particle effects are visible through the air over all cold regions. Unlike with rain, any entities that are on fire are not extinguished on contact with snow. Snowflakes fall in the two middle lines of a block; they do not visibly fall directly onto the player.

Snowflakes fall through ladders, vines, carpets, redstone repeaters, snow layers, mob heads, flower pots and cobwebs.

They are stopped by signs, banners, doors, fence gates, trapdoors, pressure plates, glass panes and iron bars.

Trivia

 * Snow actually falls one block into the void (Layer -1). This can be seen by digging a vertical shaft down in Creative mode, removing the bottom layers of Bedrock, and flying down into the Void. Note that no particles are emitted from the snow, due to the absence of a block below it.
 * Snow still falls above the clouds. Notch's explanation is that the gray above the clouds during a storm is another layer of clouds and the origin of the snow.
 * There is a never ending snowfall above a certain Y value, which turns into rain then rain turns into nothing.