[1] Each 90-minute-long programme in the series – which is broadcast daily from Midsummer's day until the middle of August at 13:00 (a timeslot held since the first episode) and repeated in the late evening – is presented by a different host who talks about a topic of personal relevance and plays music of their own choosing.

Being invited to host the show has been compared to receiving a knighthood in Sweden,[2] and it has become the custom for each year's presenters to be featured in a group photograph, each wearing a floral crown known as a midsommarkrans as a mark of the "honour" bestowed upon them.

High-profile celebrities such as the actresses Anita Ekberg and Liv Ullmann and the film director Ingmar Bergman have all hosted their own Sommar show.

Other hosts from the film industry include Academy Award winners and nominees such as Malik Bendjelloul, Kay Pollak, Tomas Alfredson, and Paul N. J.

Members of ABBA and modern music stars such as Robyn or Maja Ivarsson from The Sounds, as well as authors such as Astrid Lindgren, Håkan Nesser and Karl Ove Knausgård have been hosts of their own shows.

[11] In June 2014, Sveriges Radio received over 70 formal complaints concerning an edition of Sommar presented by the poet and playwright Athena Farrokhzad claiming that she encouraged left-wing violence.