Borgholm is a cute but quite touristy village on the island of Öland. It is good for a stop to wander through the village and grab something to eat and drink, but after that, it gets a bit boring. One of the food trucks on the main square served pretty great burgers on our visit. The ruins from the fortress "Borgholms fästning" outside of town are worth a visit, especially if you have tickets to a live performance there. I can recommend the annual festival "Borgholm Brinner".
You can expect temperatures of around NaN° Celsius in June during the day in Borgholm.