View the thread, titled "Best tile adhesive for outside tiling with porcelain?" which is posted in Tile Adhesive and Grout Advice on UK Plumbers Forums.
There is noooooooo way tiling onto plywood in an exterior situation is a good idea. Forget it. Wait until the temperature rises above 5 Degs C and then use cement backer board and tile using the best exterior grout & adhesive you can find 😉
Reply to the thread, titled "Best tile adhesive for outside tiling with porcelain?" which is posted in Tile Adhesive and Grout Advice on Electricians Forums.