How cold is "cold" and how long do you want to wait? Even at temps just over freezing I think most epoxies will eventually cure. It may take weeks. My basement shop stays between 55 and 70 year round without heat. Even at 55 degrees MAS resin with slow hardener is fingernail-hard and sand-able overnight, with no blush. US Composites takes twice as long with medium, with blush. MAS is pretty thin even at that temperature so it's good for overcoating. When I want to laminate cloth I like to warm up the shop to about 85.

To aid penetration at lower temps some people thin down their epoxy with denatured alcohol or acetone. I would caution going down that route unless ok'd by the manufacturer. It can leave to weaker, more porous coating of epoxy. I'm sure others will have more words of wisdom on that subject.

Dan