Sometimes it's so hot that the best thing to do is get out on the water. Do as little as possible and maximise your enjoyment of the sun and heat. Save the long trips for another day. Lake Seljordvatnet is long and very nice to have a boat on. All the fine campsites @seljordcamping, Sanden Camping, Telnessanden Camping, Garvikstrondi Camping As and Seljord Ferieland AS are beautifully situated next to the lake, all on their own sides of the lake. And they seem to be fully booked for the holiday. Think 30 degrees and little wind. It's perfect boating weather.