Sunlight Checker: Sun & Shadow

Will your next home actually get sunlight? "South-facing" on the listing doesn't tell you what the buildings around it do to the sun.

Sunlight Checker computes real sunlight hours for any address in Japan's major cities. Tap the map and it simulates the sun's path for all 12 months, using the Japanese government's official PLATEAU 3D city model to account for shadows cast by the surrounding buildings. PLATEAU reflects buildings as of the date they were surveyed, so buildings constructed or demolished since then may not be reflected — the results screen shows the survey year so you can judge.

FREE FEATURES
- Sunlight hours per month and yearly average, scored S to D
- Floor selector — see how sunlight changes from the 1st to the top floor
- Building details: height, storeys, zoning, building-coverage ratio, floor-area ratio, flood and landslide risk (PLATEAU attributes, availability varies by city)
- Save up to 1,000 favorite locations
- 3D map and satellite imagery
- iPhone Duo support: unfold to see the details and the map side by side

PRO FEATURES
- Hourly timeline in 15-minute steps
- 3D shadow visualization, with a one-line answer: does this floor get sun at the time you pick?
- Direction filter (south-facing windows only, etc.)

COVERAGE
Tokyo 23 wards, Yokohama, Kawasaki, Osaka, Nagoya, Fukuoka, Sapporo, Saitama and other major cities.

PRIVACY
All computation happens on your device. Searched addresses are never sent to a server.

Note: The app interface is currently Japanese only. The map and numeric results are easy to follow, and this page's screenshots show exactly what you'll see.

Privacy policy: https://sunlightchecker.remosia.biz/privacy.html
Terms: https://sunlightchecker.remosia.biz/terms.html

Building data: Ministry of Land, Infrastructure, Transport and Tourism (MLIT) PLATEAU, adapted (https://www.mlit.go.jp/plateau/)