It will cure when the temperatures rise again, but that could now take days at a reasonable temperature (above 60F) before you get a non-tacky surface.
By the way, had you not had rain and a temperature drop the tacky surface would be ideal for painting. Paint adheres very well to tacky epoxy.
But that's not the real problem here. The real problem is that you likely have moisture trapped in the resin. This could eventually work its way into the fiberglass layer and then cause the entire structure to de-laminate. It could take months or years for this to happen or it may not happen at all.
The only reason I can't tell you for certain is that it would require a microscope and tearing the laminate apart to see if there's been enough water incursion to cause problems. Hardly an ideal situation.
I wish you luck on this. I wish I could be more specific, but it's just not possible even with all the information you've provided.