I want to get laser treatment for melasma, but will it be less effective if I get it in the summer?

I've been looking into laser treatments like Pico Toning lately because of my melasma, but I'm hesitant because people around me are telling me not to get the procedure in the summer due to UV rays.
I've heard that it can actually get darker after the procedure. Is there actually a case where that happens?

I want clear skin, but I'm stressed because of my freckles.
Would it be more effective to receive it in the winter after the summer?