What is the working temperature for this product? And does humidity affect the mixture?

The ideal working temperature is 65–75°F in a clean, dry, dust-free environment.

Epoxy resins are affected by temperature and humidity—so the cooler and drier your work area is—the better the results. Avoid working in high humidity. If you are pouring in large volumes of 2 gallons or more, we suggest keeping the room temperature closer to 65°F. We highly recommend keeping fans on your project to help dissipate the heat.