I've been using Passport to World band Radio for several years now. The SW
listings refer to programming skeds as "Winter Only at thei time" or "Summer
Only at this time".

My question is, when exactly does winter programming end and summer begin? Is
it at the Spring Soltice or something? Does it depend on the individual
broadcasters?

Thanks for any help in clearing this up, I've always wondered about it.

---Ken