Tool · Sunlight
How many hours of direct sun does this window get?
“South-facing” is a label; the answer is a number. The map puts the real sun over the Lands Department's 3D model of the city — every block around, and the hills behind — and measures one window: when direct sun arrives, when it leaves, and what stands in the way.
What the sun tool measures
Hours of direct sun
For one window — a floor and a facing — on any date: minutes of direct sun out of what that wall could get.
Open in the mapThe blocker, named
Which building takes the sun, how much taller it is than your window and how far away.
Open in the mapHills on the horizon
The far skyline counts too — in Hong Kong, a mountain can end the afternoon before any tower does.
Open in the mapThree views
Around the block, square to the wall, or from the window looking out — switch with one tap.
Open in the mapAny day of the year
Winter solstice for the lowest sun, summer afternoons for west sun — drag through the day and watch it move.
Open in the map
Try it on a real building: K11 MUSEA, Tsim Sha Tsui
This is the map itself, open on K11 MUSEA with the sun tool on — the Lands Department's photo-real model, every block within 800 m, and today's path of the sun.
Try this
- 1Click any window on the building — the card names its floor and facing, and counts the hours of direct sun.
- 2Or pick a floor and a facing in the bar at the top of the map.
- 3Drag the time along the bottom to watch the shadows move; change the date to see winter and summer sun.
- 4Switch the view — around the block, square to the wall, or from the window looking out.
- Sunlight is computed, not photographed: the sun's position for the date and time, against the Lands Department's 3D models and government terrain.
- Buildings without a Lands Department model can't be measured yet — the card says so rather than guessing.
What the sun tool won't tell you
Light inside the room
We measure direct sun on the outside of the window — not reflected light or how deep it reaches.
Cloud and haze
The result is for a clear sky. Hong Kong's actual sunshine hours are lower; the Observatory publishes them.
Towers not built yet
They count once they are in the government 3D model. Approved schemes show as planning applications.
Measure the window, not the brochure
Tap a building, choose floor and facing, drag the time.