It's less likely to rain at GeekCon festivals now, which should help keep those computers safe!
Fixed in Patch 1.58.63
The forecast isn't synced between worlds like it is between neighborhoods in the same world. Since festivals run in a 2-week cycle, you could visit the area within a week prior and look at the calendar for a forecast during the event. Note the festival itself doesn't appear in the calendar, so you'll have to look for the day it should land on.
Beyond that, this might be a topic for The official Bad Randomizer Complaining Thread.
I've merged this with the geekcon rain issue thread although yours is a bit different. Guess it just wouldn't matter as much if the stuff wouldn't break.
As @SDPhantomGamer the bad randomizer thread would have been another option to merge
