A distant (15mi or so) severe thunderstorm, especially when out on a quiet field. You can just barely make out the thunder and all and I get this soothing calm that feels like a low rumble. It is not an audible rumble like what thunder makes, it kind of just triggers a sense outside of my normal five that I'm pretty sure has to do with electricity or electromagnetism. With that sense, I can tell when there is a device powered on in another room even if it makes absolutely no noise at all.