Condensation in headlights

When I came out this morning I saw that one of the headlights had a little condensation on the inside of the headlight housing. It wasn't a lot but it was 11:00 am and it hadn't gone away. The nights get cold here with the last few nights dropping between 10-25 degrees. Is there anything I can do to prevent this from happening?

Another issue I have is that the housing that contains the high beams has this black stuff under the seals. I don't know what it is but its not suppose to be there. I'll try to include a photo in the morning, its too dark out right now to take one. How would I clean it out?