Ryan, Did you use a Redwood Stain with a Water proof-er in it or just plain Redwood Stain? The plain stain doesn’t have any water proofing in it,but it is a oil based product and anything that has oil in it will protect it up to a degree. Some products recommend you waiting so many days before re-coating it with a water proof. That is to allow it to cure completely. If it hasn’t had enough time, the finish might have some oil still on it and that would interfere with the application of the water proof. If your stain doesn’t have the water proof in it, you might look a few brands of water proof over before you buy. One of them, Thompsons Water Seal, recommends you wait forty five days before applying. That right there is the only reason I don’t like them. That is why I suggested you look a few different ones over. You could also use some Linseed Oil. That is a good water protector for wood. If your can says wait twenty four hours, you better follow what they say. I don’t think the dew will interfere too much.