ToME: the Tales of Maj'Eyal

I finished Ukkis quest, and when I enter Derth, the dialogue informed me that the clouds are cleared, but the town's still dark...

Are you still hearing the thunder, and seeing lightning flashing? Maybe you're just seeing the normal nighttime darkness. Which is a real pain in the ass IMHO.

I see this too, and I have night time turned off. I always just ignored it, as it had no gameplay effects.

Same here. I just assumed it had something to do with the tileset that I was using, so I just ignored it. Though I think that it would be nice if after the storm was cleared the townspeople would come back out of their houses and shops to populate the town again. Right now the only ones that you will see after completion of the quest are any that weren't killed off by the elementals.

Same, thunder noise and lightning effects cease, but it remains dark forever, day/night cycle is not resumed.