How long does herpes last on a cold surface?

It doesn't matter. Herpes simplex virus (HSV) is not transmitted by contact with surfaces. Herpes is caught only by direct contact with the infected body part of someone with HSV, i.e. by kissing, sexual exposure, or other intimate contact. You won't catch it by exposure to "surfaces" (whether cold or warm), doorknobs, towels, or shared toilets, kitchens, eating utensils, drinking glasses, and so on.