On a clear day in June the terrace has sun 13:30–15:00 and 17:40–20:00, about 4 hours in total. In short: evening sun until 20:00.
The story of Wedholms fisk
Wedholms Fisk sits at Nybrokajen 17, with its entrance on Arsenalsgatan, near Nybroviken. The restaurateur Bengt Wedholm opened it in 1985 as a restaurant serving only fish and shellfish, still a rare thing in Stockholm.
It won a Michelin star the year after it opened and held it until 2006. Sole meunière is a fixture on the menu, and in August there are crayfish from Lake Vättern. The restaurant is now part of Melanders Group.
Sources: Wikipedia: Wedholms fisk · Wedholms Fisk · Visit Stockholm: Wedholms Fisk
How Stoligt works it out
Every ten minutes we draw a line from each terrace toward the sun and check whether a building or hill is tall enough to block it. Building heights come from OpenStreetMap and ground heights from Lantmäteriet, the Swedish mapping agency. The times assume a clear day, so clouds are not included here. They are on the live map, which shows today's weather.
Trees, parasols and awnings are not in the model, and we don't know exactly where on the pavement the tables stand. Treat the times as an educated guess, often accurate to within ten minutes.