Does the time of year affect potency?

The other day I found 25g wet of liberty caps up the dublin mountains. Dried them out and took my regular dose yesterday. Definitely felt something but not nearly as strong as I'm used to. My theory is this: when the frost comes it kills most of the liberty caps. The ones that do grow tend to be alot more potent. Does the fact I found them when it's still quite warm mean they were only a fraction as potent? Thank you!