WD40 attracts dirt like a magnet, remember? A lot of people foolishly
spray their marine engines with WD40, only to see that a year later the
electrical connections are corroded, because the oil left over has
attracted dirt and that dirt has attracted moisture.
If you are worried, then best to get a dry out spray for electrical
equipment (have no products in mind right now). But from years of
working in the rain on the west coast of BC with power tools, most
power products do hold up well enough after being rained on, or worse,