A thunderstorm is a fairly rare weather condition which takes place randomly during rain, snowfall, or dry desert storms. All changes from these weathers apply, though since lightning occurs and the light level falls to 10, thunderstorms are distinct. Even in the middle of the daytime, hostile mobs will be able to spawn, acting as if the light level had been reduced to 5. However, fewer mobs will spawn relative to night.
Lightning is a lethal element to the storm. It strikes randomly across the Overworld, creating brief fires. While most are put out almost immediately by the rain, it is possible for it to ignite wood and other flammable blocks. Lightning striking uses the same sound as TNT or a Creeper exploding, or at least until the Beta 1.8.1 update which changed the sound of a TNT explosion, as well as a few other sounds.
- Thunderstorms are darker than normal rain, at light level 10 during daytime. Hostile mobs are allowed to spawn, as though the light level was at 5, nearly as dark as night. Like rain, thunderstorms won't reduce the light level below 4 at night.
- Thunder can be heard by the player up to 512 blocks away from where the lightning strikes.
- Lightning creates fire where it strikes. The accompanying rain can usually put out fires before they spread. Overhangs can prevent rain from putting out lightning fires, allowing the fire to spread.
- If lightning strikes a pig, it morphs into a zombie pigman. However, if The Player's difficulty is on peaceful, the zombie pigman immediately despawns.
- If lightning strikes a creeper, it becomes charged and has a much more powerful explosion. Additional strikes will not make the explosion any more powerful, but may kill the creeper.
- Being struck by lightning or standing near a lightning strike deals two and a half hearts of damage, not including damage from the fire.
- If lightning manages to strike a portal frame, it will activate the portal.
- The player can sleep in a bed during a thunderstorm, regardless of the time of day.
- When lightning strikes an entity, it can disappear.
- If lightning strikes a boat, the boat will disappear and usually destroy the drops.
- If lightning strikes floating sand or gravel, it will cause it to fall.
- If lightning strikes a painting, it will cause it to fall off of the wall.
- If lightning strikes a mob (except pigs) it will cause it to take damage.
- If lightning strikes and kills the Player, they will disappear without dropping anything, as opposed to dropping their items and experience orbs.
- If lightning strikes a minecart, it will break the minecart and usually destroy the drop.
- Like normal rain, thunderstorms are harmful to Blazes, Endermen, and Snow Golems.
- If lightning strikes TNT it will ignite.
- If lightning strikes close to the player, an explosion sound will be heard at the same time, as well as the thunder.
- Under the new 12w34b version, thunderstorms cause a lot more damage in harder gamemodes, due to the fire it creates.
- Lightning can still touch down (from a nearby storm) in dry biomes such as Deserts, with no rain to extinguish fires.
- Lightning, unlike other weather, does not have an image file associated with it. Thus, it is coded directly into the game engine, allowing for dynamic, realistic lightning.
- Lightning can go directly through blocks to hit the ground.
- As long as you are within 512 blocks of lightning, you will hear it the same time as you see it.
- You can hear thunder all the way down to the bedrock layer, even when falling in and suffocating in The Void in the Overworld. Just like ambience, thunder is not an indicator of anything but areas that were struck by lightning.
- The new lighting system in Beta 1.8 introduced dynamic lighting effects. Each lightning strike will now briefly light up all the topmost blocks, creating a more noticeable flash.
- Lightning cannot be seen through water. Similarly, when looking at water through a lightning bolt, the water is not visible.
- Forest fires made by lightning are rare unless the lightning strikes underneath a tree where the rain won't be able to extinguish the fire.
- If lightning strikes between you and your line of vision to a lit End portal, the End portal (minus the frame) becomes invisible during the strike.
- Lightning can occur in the Taiga and Tundra biome types.
- If the player is killed by a lighting bolt in SMP, the death message will read: [playername] died.
- Lightning strikes create an explosion effect and sound but won't destroy blocks.
- There have been reports of lightning strikes without a representing storm.
- Lightning sometimes has odd effects with redstone, like causing dust to become suddenly powered or forcibly turned off. Its unclear if this is intentional.