How long does it take to cure?
"Curing" or "Vulcanization" Times
You will notice the product is dry to the touch with-in a few hours, and will be waterproof. However, the rubber is still going through a very important process called "Vulcanization" - this is the process where the rubber becomes one single membrane and can contain water on a continuous basis. The process of "Vulcanization" takes 7-10 days. Depending on temperature and humidity SEE BELOW. days.
You do not want to expose coating to chemicals or continuous water saturation until the vulcanization process is complete.
If you have a question about your specific applications please do not hesitate to contact us either via the phone, e-mail or our live online support chat. We are here to help!
If the product is not properly cured and you fill with water, you will get little gas bubbles
Optimal vs. Acceptable Humidity Levels
Optimal relative humidity (RH) levels for exterior applications tend to be in the 40-50% range or lower.
Levels of 70% or greater will "drastically slow drying and curing," but again will not prevent you from applying.
Applying above an RH level of 85% is strongly not recommended.  The coating will remain gummy and gel-like until the RH lowers to an acceptable level long enough for it to solidify.  
However, because the coating has not been allowed to "level" properly, the texture will remain wavy and otherwise unacceptable.
Temperatures Work With Humidity, Too
One tip is to time your application so that temperatures are on the rise--several hours before the day's peak temperature, which is usually in the late afternoon.  High humidity will slow dry time.
You need to build in a head-start by beginning hours before you think it is time to begin:
Even though the temperature was OK at the time of application, the coating can stop coalescing. This permits moisture to get into the uncured paint film allowing certain ingredients to come to the surface when the moisture evaporates, causing surface staining and possible adhesion problems.