Valborg, the bonfire night on April 30. I've written about my first Valborg in Sweden before.
There's an advantage of arriving at this time of year. The island community has a number of clean-up events in early May. Typically, I haven't been able to attend those, preferring to save my vacation time for later in the summer.
Now, though, I have lots of free time, so we will stay longer, and be part of Aspö's clean-up this year. I'm looking forward to it!