When worn during Rain, the player's Wetness will not increase at all. Additionally, it insulates the player against Lightning strikes and the electric shocks of a charged Volt Goat. Rain Coats are tier 1 warm clothing, providing 60 insulation from Freezing.
Rain Coats last for 10 days and a Sewing Kit will repair 50% of its durability.
Playing as WX-78, the Rain Coat complements the Telelocator Staff, as it can be used to negate the sanity penalty of the second lightning strike when casting it on themself (one must be sure to equip it quickly though if only protecting against the second strike).
When fighting Moslings the Rain Coat can be handy to protect against the frequent lightning strikes that will occur, while still allowing armor to be equipped in the head slot.