Hi @JSpaxcz
what does the weather forecast say ? This has been an issue for people with mods but you say you don't use any. Is it raining in winter too or is it snowing there ? Did you try a fresh save for testing purposes as well as repairing your game ?
Not sure where the above poster means but in my game I have found, weather forecasts are only for area you live, my Sims live in oasis springs so they weather forecasts are pretty good. Unfortunately the outdoor dance party's are in Windenburg, The Bluffs, Van haunt estate. I have given up sending my Sims to these, as there really is nothing to do but get uncomfortable and soaked. Never sent them in winter, but it really does seem to rain a lot, in windenburg.
Its properly more tuning, or areas needs redesigning as windenburgs weather, no longer seems suitable for outdoor party's.
Moving this to tech issues for further troubleshooting and info
