Suposibly it less the THC potency. I myself have dried in dark, in room with no window shade, and in a corn field with the sun. They all tasted great and did the trick. But you "should" dry in the dark.
Nothing really. They say light degrades THC but if your drying room isnt completely dark Im sure youll be fine. Just make sure its nice and cool with good air movement. It would suck to get mold after waiting two months. Hope it helps