On a clear day in June the terrace has sun 15:30–18:20, about 3 hours in total.
The story of Restaurang Hong Kong
Restaurang Hong Kong has been on Kungsholmen since 1963, making it one of Stockholm's oldest Chinese restaurants. The restaurant itself says it was the first Chinese restaurant in the city. The menu covers spicy Sichuan dishes, Hong Kong specialities and Peking duck.
Sources: Restaurang Hong Kong · Thatsup: Restaurang Hongkong
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.