Once the wind is strong enough to blow possums out of a tree, only then do I start considering packing up,
Like Zero says - too many variables: your mount and then the scope you have set up on it, your location (protected or not), what you are trying to achieve, etc.
If you have a stout, heavy mount and only a little scope set up, wind will have less of an effect than a lighter duty mount carrying a large scope that becomes a sail.