Where do Snails Come From When it Rains? 

Where do snails come from when it rains, and why?
Snails come out of their hiding places (under rocks or about 3 centimeters underground) when it rains for multiple reasons.
Firstly, snails are mostly made from water, and so they come out because they need to keep moist. In dry weather, they can create dried mucus barriers with the stored moisture to prevent water loss and survive for years.
Secondly, snails breathe through their skin, and can drown if they stay in their hiding places.
Thirdly, when it rains snails can move around much easier and there are less predators. They may crawl onto the wet smooth pavement and keep moving in a straight line trying to find their way back into undergrowth for some food.
Lastly, snails look for a mate in the rain. Since they are hermaphrodites, these creatures simply need to find any other snail in order to impregnate each other.