Sommartrail is a 30 km trail run in Sollentuna, north of Stockholm, starting from Ytterby at 02:00 on the longest day of the year. The event focuses on running through the last dark hours and into the summer dawn. Runners participate after midsummer celebrations, heading out to meet the early light. The field is capped at 100 people, maintaining a small, personal atmosphere rather than a large mass-start race.