I thought it would be cool to come up with a weather mechanic similar to day/night in the recent Innistrad sets. Bear with me here, I know it's a bit overcomplicated- But it would basically function based on creatures attacking to determine the weather next turn. Thoughts?
I found some problems though it will be flavorfully nice mechanism if finely tuned.
Name In my knowledge of English, they are not bound by weather as nightbound is bound by night. Wethercall is better I feel.
Mechanism Difficult to learn. Night & daybound is also not easy to learn. Most of you would ever missed the condition some times. But they are only two and their conditions are paired. So once you learn it, you would remember it even if you left magic for a decade. This is more hard than it.
Flavor This is another reason nightbound is difficult. It is not intuitive. Cycle of night and day is generally uncontrollable. The night, which you call by doing nothing, has a paradoxical flavor of that most of people get to do nothing but sleep because night comes or came. And this weather mechanic is more difficult. Snow attacker calls snowy is easy to understand but many attacker and stormy are hard to think a shared image.
I propose that weathers are only called by abilities except clear sky. e.g. Adventurer has weathercall -- windy and Stampeder has weathercall -- stormy. When a creature with weathercall etb or attaks, it becomes the weather. And no creature attacks, the next turn is clear sky. Some cards have other ways to call weather but it is mainly changed by attacking.