This thread mentions a fix for lmde. Well point of fact, A BUNCH of hacks and fixes for lmde from the looks of it. One of them for the prob you're having. Found this by searching the minty searchbar for "UTC lmde". I'm just going to give the whole link instead of quoting. As hopefully it's spot on for your prob. Plus looked like some other stuff ya(other lmde users) might find interesting. Don't vouche for everything there. Haven't used lmde myself but certainly can't hurt to look it over.viewtopic.php?f=141&t=76010&p=441119&hilit=utc+lmde#p441119
Nevermind the one below, it's for xfce. Which tdockery was helping someone with a spec prob that more than likely doesn't apply to you. But the other one should.
One possible fix:
Open a terminal and type the following.
sudo gedit /etc/default/rcS
Change UTC=yes to UTC=no
Click on "Save" and then close the file. See if that fixes it.
Brought to you by a forum search for UTC in the magic minty search bar and a post from tdockery97. Lol ... ironic that I'm hopefully helping you find a fix. When I have a distro that still gives me this same headache installed and haven't figured it out yet myself. Oh well ... it's not my fav. Don't boot it as much as I once did and will get around to it. As long as I don't boot it up, system time stays where it should.