Seems like most community choirs follow the academic year, starting in September and giving their final concerts in May/June. For children's choirs, this kind of makes sense, but I'm not sure why adult choirs do it, other than force of habit.
But some groups have special summer events, ranging from one-day workshops or reading sessions to full concerts. What has your group done in the summers? Do you find you get a different group of singers in the summer than during the school year? Does it help keep your momentum for the fall? Share your ideas!