For temperature, I don't have a limit in michigan weather. The temps here aren't too extreme, so I'll ride in whatever. This year I had a night road ride at 12F and felt perfectly fine once I got moving. The heat here only gets mid-upper 90s with high humidity and I'll ride. I think the heat has more of a effect on me than cold.

I don't ride in heavy rain or snow at all. If it's a really light rain, I'll ride road or trail (assuming the trails are dry). Light snow, I'll ride trails. I don't recall ever having strong enough winds here to make me not go out or regret going out. It just isn't something we have much of. Last week we rode with 23mph winds which I found pretty tough, but REALLY fun on the way back! I'm guessing 30mph winds would be my cutoff point.