Does rain effect the trichomes? If it rains long and hard enough will it wash off some of the trichomes? Will it effect the potency in any way?
Yup, you have that correct. Heavy hard rains will knock off the trichs. IMO, it probably does effect the potency. The trichs no longer have that "bulb" at the top, if you know what I mean? Apparently that is where mostly all the THC is.
if it rains heavy before you harvest then let it dry out again as much as possible untill you have to take it....it should brighten back up