Camera nesting box

Hi, new to this so apologies if this is a basic question! I've got a new nesting box with a camera and cable. To get the cable into the house I have to leave a window (securely) on a 'latch'. I don't want to leave it too late to connect as it could disturb the nesting process, but am reluctant to 'let the weather in' particularly if we have lots more wind and rain! (Live in the soggy South). Any advice as to when to connect or how to keep the weather out? Thanks. Probably helpful to know that it'll most likely be blue tits or great tits that'll nest.