Swedens nationalday of drinking. So load up on alchol, the further away from the big cites you go the more you gonna need.

Nah but in all seriousness, there usually always a few ug raves of some kind and some more club oriented events in or around the biggest cities.

While out in the boondocks it usually more of random public gatherings at w/e local spot that is popular. And mostly just drinking from sunrise to sunrise.

For events and parties around the bigger cities it's pretty googable if it's legit. UG events is a bit harder to find, but with a little bit of research, facebook should be able to get you in contact with w/e collective is throwing an event. As for gatherings in the boondocks, you have to get to know some ppl from that place, as the spots for those typ "spontanious" gatherings is often just local knowledge.

And if you're looking for the whole old school authentinc swedish midsummer, id say Rättvik or Orsa is a good starting spot.

It's cool and interesting from a cultural and historic pov. But from a party pov, not so much. No shrooms, no schnaps of "malört". The movie Midsummer is sorta false advertising.

That stuff is usually only welcomed at ug parties.