The topic of weather generation is popular among sim GMs. The answers boil down to either random tables or using an almanac to find relevant weather from a place/time similar to the campaign’s.
Since I run a naval campaign, specific temperature, wind, etc. is an important part of the game to me and my PCs. I was using a random table method (using tables cobbled together from several sources because no one source has tables that are complete and don’t suck) – but I think I have a new plan along the almanac method line!
Enter VentuSky. Frickin beautiful isn’t it? An animated map of temperature, wind, etc. for every hour of every day. Wind… Waves… All the info you’d ever want. And on Golarion most areas are “Earth-like” – my PCs are sailing down the coast of Garund, which can be easily mapped one-to-one with the African coast. In fact, use this very cool interactive Golarion map to set up equivalencies!
The only problem it’s a short window forecast instead of all historical data, so you’re kinda stuck to same time-of-year as current IRL, but I thought I’d share it anyway! I emailed them to see what the chance was of getting historical data in there as well… I’ll update you!