If you feel the weather may be an issue when prepping and coating your pool, consider the hire of a Marque or build a tent. Either way make sure its well anchored (best not to leave up if strong winds forecast) and ensure good ventilation when working underneath. With a “tent” what can happen is the wind will collapse the poles holding up the middle and then all the water and leaves end up in your pool on the wet paint. SO make sure the “tent” is well constructed and that the poles cannot move. See the pictures for some ideas.