Welcome to the forum, I have the same engine in a side x side, the 450i UXV. Mine sits in an unheated barn and starts great. I do keep a battery tender on when the cold is extreme as it is now, because I use it to plow snow. As far as your quad goes, does it have an ignition kill switch? Is it on? I guess the real question is..is it under warranty? If so let the dealer figure it out. Any possibility the fuel line is frozen? A quick check of the plug to see if it is wet and check for spark, a nice blue spark is needed. This time of year I do add marine stabil (blue) to the fuel to prevent icing and water in the fuel.
Keep us posted on your outcome, please...