Start with a riverfront search area
Ribeira das Naus runs by the Tagus between Praça do Comércio and Cais do Sodré. It offers a clear geographic starting point for a waterside walk. Locate actual seating or a venue before comparing its sun exposure; not every open public space is a serviced café terrace.
Check which direction is open
An open river view removes some nearby obstructions in that direction, but sunlight may arrive from another side during your visit. Identify the exact position and look at the surrounding buildings at your planned local time. Do not assume every riverfront seat remains sunny for an entire afternoon.
Treat hillside viewpoints differently
Lisbon's hills create views, slopes and local horizons that a building-only shadow map cannot fully describe. A viewpoint may look open toward the river while a slope or structure blocks the sun elsewhere. Verify the horizon from the location and keep an alternative nearby.
Include the uphill walk in your timing
A short distance on a map may take longer when it involves a climb. Compare the shadow for when you expect to sit down, then check the end of the visit too. If your goal is a relaxed coffee, a riverfront option near your route may be more useful than a distant “best sunset” recommendation.
Adapt to the season
Low winter sun and high summer sun interact differently with buildings and covers. In warm weather, a terrace with shade can be preferable. Check current weather, venue hours and the actual canopy or parasols separately from the geometric map.
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.
