IP 65 is a term used to describe how waterproof something is. If something is rated IP 65 it is stated to be able to withstand “water projected by a nozzle (6.3 mm) against enclosure from any direction”. IP 66 can withstand more powerful jets of water, and IP 67 can withstand immersion into water up to 1 meter. For planning events in the outdoors, you’ll want to try and acquire as much IP 65 rated audio and video gear as possible to avoid having to cover them up / discontinue use in the case of light to moderate rainfall.