Lightning occurs naturally during heavy Rain, striking up to 10 units away from the player. Mobs and objects within a 3 unit radius of the point of touch-down can be set on Fire. Lightning can also strike the player through unnatural occurrences (none of which will cause any Health damage); Touch Stone resurrection, using a Telelocator Staff, or damaging an Ancient Pseudoscience Station.
A Lightning Rod can be used to safely attract lightning strikes within a 40 unit radius (about 10 Pitchfork tiles), and will emit Light for roughly two days after being struck.
In the Reign of Giants (RoG) and Shipwrecked (SW) DLCs, lightning can strike the player, dealing 10-20 points of damage, depending on the player's Wetness. Wearing any piece of insulated clothing will prevent damage from lightning or electricity.
In RoG, Volt Goats will attract lightning strikes in the same manner as Lightning Rods. When struck, they become charged (making them aggressive). Charged Volt Goats deal additional electricity damage, and can drop Electric Milk when killed. Eyebrella, Rain Coat, and Rain Hat are the insulated items available in RoG.