It won't be a surprise to many, then, when there's an explosion of sound once the sky is dark, and blinding flashes through the sky.
And then more, and then more, and they're all sorts of colors...and as it turns out, it isn't lightning at all, it's fireworks. Flying from beneath the castle to explode high. Dropping from above the castle to burst just below the Edge where anyone who gathers can nearly touch them if they dare to get close enough to risk a fall. Some from the sides in a way that should be impossible--there's only clouds in every direction, isn't there?
It's not only the sky; here and there are piles of the stuff on the flat-topped towers, littering the grass along the Edge, with tinder and matches where anyone can reach. Simple little sparklers and poppers, too, for those who can't or won't risk anything larger.
It ends when the horizon begins to lighten...but the fireworks people can use on their own are still strewn about.
The sky sears again the next night, just as loud and bright if not moreso.
And the next, and the next, and the next...
//For a week, which irl will be from about July 23rd to July 30th, there'll be fireworks lighting the sky every night! Here's the post to have your characters hang out and enjoy them together! Or not.