How long to wait between sealer coats

Wait until the surface is no longer sticky/tachy. The surface should feel smooth and non tacky. Typically the instructions indicate the humidity and temp range to use the product in. Sounds like the rain is the problem. Under ideal conditions you can sometimes recoat in as little as 4 hours. In cold or humid conditions the wait period can be several days or until the weather dries out and or warms up.

More important, what is the temperature? The lower it is, the longer it takes.

Is the coating still tacky or is there enough condensation on it to just make it feel that way? If it's tacky then somthing is wrong--polyurethane (at least single-part oilborne polyurethane) requires moisture to cure so high humidity shouldn't cause it problems.

Huh? I don't think so.

Leon is spot-on. low temps and high humidity slow down the curing process.

-Steve

The process of curing should obey Arrhenius's equation, so as a rule of thumb, every drop in 10 degrees C halves the reaction rate (curing process).

How old is the poly? Most finishes have a 1 year shelf life at best.

If it's fresh, did you cut the poly? First primer coat works better if thinned 50%.