I'm not a fan of outdoor parties in winter. I don't mind having a play outside but not for the duration of a whole party. DS gets sick at a drop of a hat and cold weather does make it worse.

There are some nice play centres if you look around. I found one for DS that is a disco party room so no play gym. Just party games, food and dancing then home without any cleaning up. I've got a reflux baby so it's the first time I'm not doing it at home as I'm exhausted.

Good luck with it