Flew my Phantom 3 Adv today. Temperature was about 35 degrees F. After about 10 minutes I lost all video feed back to the remote control. . Drone was only about 40 feet away. I took it back inside and let it warm up. When I restarted it video feed had returned.

Never had this happen before. Any ideas.  Anything I should check on?

Did you tried to adjust the antenna when it starts to lost signal?
Please go to another open area and test again.
If you want to fly in low temperature, please remember to warm up the battery first.
Here is the screenshot for your reference.

I had just taken the Phantom from inside my house to my yard to fly it just above my house - inspecting my chimney looking for signs of where squirells could get inside. Was taking some still shots around the chimney about 25 feet above the ground. Battery voltage was fine. Camera was working fine. All of a sudden after about 10 minutes of flight the video feed went blank and I got a message about it. I tried reorienting the antennas but feed never came back.   
    I flew drone back to my driveway and landedthe video feed was still out.  Itook it inside and just let it sit on a table for a while then turned it on and video sudenly reapeared on remote. i am going to fly it today and see if all is ok.
   Just can't see any problems with it. Will post results of test flight.

I just had this happen to me today too.  I am in warm weather so that is not an issue.  I recently updated the DJI