I admit I'd like to know when the storms come for Gigas, but since we DON'T know if the weather is randomly controlled their might not be a schedule to post with for them since it is random and on the fly. THough if the system is buffered over say an hour, then we can get an idea of the next hour.
If that is the case why not use the NPC in town named Wesley the meteorologist as the forecaster for hints at timing of storms, and does so with four 15 minute percentages. This means it won't be a straight answer, but now you could know that there could be a 80% chance of storms in the next 15 minutes with a 30% chance of storms in the next 30 minutes. It'll hint that a storm will be very likely coming in the next 15 minutes, it'll keep random, but those hunting gigas can now get an idea of the giga forecast for the next hour.