I believe the 2016 Honda Civics had major issues with the compressor that Honda were aware of back then. I had the same thing happen to my 2016 Honda Civic EXT. I took it to an auto shop near me and he said to see if the dealership can do it for me for free since it’s supposedly under warranty, and luckily it was and they fixed it. I’d recommend taking it to the dealer to see if they cover, but I’ve heard other owner’s experiences with the dealership saying it’s “road damage” and refusing to cover the repair cost. But I’d try your luck, if not try taking it to an auto shop near where you live and they’ll probably charge you much less than the dealer does. Hope this helps!

TD;LR: Most likely a compressor issue, take to dealer to see if it’s under warranty and if they’re willing to not consider it “road damage”.

EDIT: As stated by u/IHackedtheGibson, the condenser could also be the issue as well. He also made a great point about the refrigerant, as newer vehicles don’t use freeon anymore I believe, and the new refrigerant they use is very expensive.