Start with a riverside route
The official Tokyo tourism site describes riverside walks and the city's waterfront areas. Along the Sumida, choose a specific stop near your route rather than assuming every stretch between neighbourhoods shares one exposure.
Inspect the actual outdoor area
A venue can have a small terrace set back from the river or under a roof. The entrance pin does not establish the seating position. Look for bridges, elevated structures and covers near the table; a building-shadow map may not represent every structure in sufficient detail.
Compare a street option too
A riverside seat can have a wider outlook, while a nearby street café may offer a shorter walk or more shelter. Tall buildings can cast shadows across both. Choose based on the conditions during your visit, not on a general waterfront label.
Use destination time when planning travel
Set the date and local Tokyo time you expect to arrive. Include the walk from the station and check the end of the visit as well. If the shadow edge passes across the seating midway, compare a second nearby option.
Check weather and seasonal details
Cloud conditions are separate from building shadows, while seasonal foliage can change garden seating. Coffee in the Sun does not include trees, awnings or terrain in the building model. Verify these on site, and confirm current venue opening hours directly.
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.
