I'm guessing you're talking about crimson clover? Red is a perennial or biennial. Crimson won't die from a frost, it takes temps around 15 degrees or so to kill it. In years where snow comes (and stays) before temps get into the teens I've seen crimson make it through the winter.
I'm talking about the "Red Clover".
Cereal Grain combo in 45% of plot
Winter rye 50-80#'s per acre (56#'s = a bushel)
Spring oats 80-120#'s per acre (32#'s = a bushel)
Frostmaster Winter Peas or 4010/6040 Forage peas 20-80#'s per acre
Red Clover 8-12#'s per acre or white clover at 6#'s per acre (or 20-40 pounds hairy vetch and 20-30#'s crimson clover on sandy soils)
Groundhog Forage Radish 5#'s per acre
Plant in late August to early September, if following well fertilized brassicas use 100 - 200#'s of urea, if starting a new plot add 400#'s of 6-28-28
So the red clover will come up the next spring? That is the reason?