Probably half of my generation know that in fiction, trolls are turned to stone in sunlight.
But in LOTR, that fact is stretched a bit. All the battles that happened very likely took place at different parts of the day, some probably in the day.
You could argue that the smoke coming from Mount Doom blocked out the sun, but my question is does the fact that there is some daylight coming through the clouds affect the trolls in any way? Slow them down for instance?
This may be impossible to answer, but its been on my mind for a while.