According to the School for Champions, static electricity refers to the build-up of electrical charges on an object's surface. When two objects are rubbed together, some electrons on an object's surface may be transferred to the other one. Static electricity may cause shocks, sparks or objects sticking together.
School for Champions explains that static electricity is best formed when the humidity is low and the air is dry. This is because humid air contains water molecules that may accumulate on objects' surfaces and impede the build-up of electrical charges. However, it is also possible for static electricity to form when there is turbulence among the drops of water, such as in rainstorm cloud.