Why Do Earthworms Come out When It Rains?
Earthworms come to the surface of the ground in heavy rains to avoid being drowned. Earthworms stay underground most of the time, in warm, moist tunnels they make for themselves.
But after a rainstorm you may see earthworms lying on the ground and on walks. They are forced to come to the surface to breathe because the soaking rain saturates the ground and fills their burrows with water.
The worms can’t get enough oxygen when the soil is flooded, so they come to the surface. Once at the surface, they seem to get confused about where their burrows are.
They move to seek safety, but sometimes they don’t make it back into the soil when the burrows drain. Earthworms cannot live long in sunlight and cold air. If they are unable to go underground again quickly, they become very weak and usually die.