Letná offers a view, not a sunlight guarantee
The official Letná Parks guide describes the hillside park above the city. If you want a café stop, locate an actual venue and its seating. Tree cover and the local slope can make that spot behave differently from an open viewpoint nearby.
Check the Vltava bank at the exact location
The river bends, and paths, embankments and terraces sit at different heights. An open view across water clears only part of the horizon. Buildings on the sunward side, bridges or retaining walls may still affect the seat during your visit.
Terrain needs observation
Coffee in the Sun estimates shadows from mapped buildings; terrain is outside that model. In a city with hills and elevated viewpoints, inspect the actual horizon as well. A ground-map result is also not a precise calculation for a terrace on an upper floor.
Give the walk a realistic arrival time
If you climb to Letná after exploring the centre, compare the shadow at the time you expect to sit down. Check again near the end of the visit. An option on the same side of the river makes a more practical fallback than a distant café reached by another long walk.
Recheck trees and the season
Leaf cover can change garden seating substantially, while low winter sun can remain behind buildings. Trees and awnings are not included in the building model. Verify current opening hours and weather before relying on outdoor seating.
Try the building-shadow check before you leave
Open Coffee in the Sun, find your chosen spot and compare the estimated building shadows at arrival and departure. The free app includes today's timeline and three time jumps per day. The model uses mapped buildings, whose coverage and accuracy vary; it excludes trees, awnings and terrain, and cloud cover is not part of the shadow answer.
Use the five-step terrace check to interpret the result. Keep a nearby alternative and confirm the real seating on arrival.
