When to Go
Architecture can be a big tip-off: covered stone arcades, dark underground cellars, small windows, and thick stone walls were all medieval coping tactics in the face of bad weather. Bern can be cold and wet and miserable in winter, its indoor spaces warmed with fires and packed with people.
But it is mild and sunny from spring through autumn, when every restaurant that can sets up camp in the street, windows are thrown open, and people take to the river by the Marzili with unrestrained glee. Summer is warm, and July through mid-August is vacation season. Note that many restaurants close up shop for a few weeks during the summer season.