Usually 24 hrs. for Professional. Surface has to be totally dry prior to coverage because it has to soak into the wood. If it rains 5 minutes after....no worries. You'll have to sweep the water off.
A full, unsealed container will set up to solid silicone in 2 days. Best stuff I ever used for porous surfaces in 30 years as a finishing contractor. A tad expensive ($40 gal.) coNpared to Thompson's, but, well worth it.
Good luck