Spells: Circle of Winter and Circle of Summer different?

[Droog007]

Also may be of note: On this server, the shaman group poison and disease buffs are the same value/duration as the single-target spells - I've no idea if this is classic or not. I always just assumed it was a more powerful spell and not just a mana saver (if 4 or more people in the group needed it and received it, mind you).