system
Given the following post, respond as if you're commenting on Reddit:
human
Why does humidity kill static electricity?

When I take off a fleece coat in dry winter you can hear it crackle with electricity but in the humid summer it doesn't. What is it about humidity that kills the static?
gpt
Static electricity on clothes comes from electrons separated (by friction of putting it on for example) from their original molecules. The separated electron acts as a negative charge, while the left behind molecule now has net positive charge. This local charge surplusses and deficits are what makes up "static electrity".
As fleece sweaters are typically made of synthetic materials that are bad conductors of electricity, these separated electrons can not move on the surface of the sweater to reunite with their molecules and thus are kept separated. This makes the static electricity stay on the sweater.

If you now introduce very humid air around the sweater, some of the water will condense into the sweater, improving the conductivity of its surface (if even by the smallest amount). Now the separated electrons can move around the surface and reunite with a molecule that is missing and electron, evening out the electric field at that point. This makes the static electricity disappear from your sweater.