When it Rains it Pours

When Becky asked me what that slogan meant, I realized I never did "get" it, so I ought to find out. I don't feel dumb for not knowing because there are some Harvard educated people who also don't know.
Morton salt adds a "flowing agent" (calcium silicate - aka slag) which keeps it from clumping up in humid conditions. Therefore, when it is raining outside, your salt will pour freely!