Home and real estate
How to check apartment sunlight before renting
A viewing shows you the light for one hour on one day. This guide checks a rental in the SunCast app, first from home and then at the window, so you can judge December as well as the day you visit.
By SunCast team Last updated: October 14, 2026
Short answer
Before the viewing, open the address on SunCast’s 3D map to see which way the windows face and what stands across the street. At the viewing, stand at the main window, open the AR Sun Tracker and move the date to December and then June. If the winter path runs behind the building opposite, that room will get little direct sun in winter, however bright it looked on the day.
How much the building across the street matters
The sun’s height decides how tall an obstruction must be before it blocks a window. In Glasgow on 21 December the sun peaks at 10.7° at 12:16 GMT, so a building 20 m across the street blocks the midday sun if its roofline is more than 3.8 m above your window, about one storey. On 21 June the noon sun is at 57.6°, and the same building would have to rise 31.5 m above the window to do the same (calculated with SunCast’s sun calculator).
That is why a lower-floor flat on a narrow street can feel bright at a summer viewing and still lose direct sun for most of the winter. You only see it if you check a December date.
Decide beforehand which spots matter to you: morning light in the kitchen, afternoon sun on the balcony, winter light in the living room or shade on hot afternoons. Those are the places to check.
Checking a rental in SunCast
1. Scout the street from home
Search the address on the 3D map and set a winter afternoon. Mapped buildings cast shadows for the date and time you choose, so you can see whether the block opposite puts the flat’s side of the street in shade. If the flat is in another city, Street View Sun Path draws the sun’s path over the street’s panorama.
2. Stand at the window that matters
At the viewing, go to the room you will use most and point your iPhone through the window. The AR Sun Tracker draws today’s sun path over the camera view, so you can see whether it passes in front of the window or behind the building opposite.
3. Move the date to December
Switch to the winter solstice and watch where the lower, shorter path falls. If it sits behind rooftops for most of the day, expect little direct winter sun in that room.
4. Check June and your move-in month
Repeat for June, when the path is higher and starts and ends further north, and for the month you would move in. The June path shows how late evening sun reaches a west-facing room.
5. Book the second viewing at the right hour
Sun Times & Position Data lists sunrise, sunset, azimuth and elevation for the address and date. If the first visit was overcast or at the wrong time, use them to book a second viewing when direct sun should reach the room.
SunCast features for a flat viewing
The map and Street View features help before you go. The AR view is for the window itself.
| SunCast feature | How it helps |
|---|---|
| 3D shadow map | Shadows from mapped buildings around the address for any date and time. |
| Street View Sun Path | The sun’s path over a Street View panorama of the street, for flats you cannot visit yet. |
| AR Sun Tracker | The sun’s path for any date drawn over the live camera view at a window or balcony. |
| Sun Times & Position Data | Sunrise, sunset, sun elevation, azimuth and day length for the address and date. |
Common mistakes
Judging only by brightness
A white wall opposite or open sky can make a room look bright without any direct sun reaching it.
Ignoring winter
In dense streets and on lower floors, winter is usually the season that decides whether a flat gets direct sun.
Trusting window direction alone
A south-facing window can sit in the shadow of a taller building across the street all winter.
Limits
The 3D map uses mapped building shapes, so street trees, balconies above you and recent construction may be missing; check those from the window. SunCast does not replace a professional daylight report, a legal property disclosure or an in-person viewing.
Check it in SunCast
Viewing a flat soon? Open the address in SunCast first, then take the AR Sun Tracker to the window and check a December date.
Frequently asked questions
What direction should apartment windows face for sunlight?
In the northern hemisphere, south-facing windows usually get the most direct sun, east-facing windows get morning light and west-facing windows get afternoon light. In the southern hemisphere, north-facing windows get the most. Nearby buildings, trees and floor height can change the result.
Can I check apartment sunlight before I visit?
Yes. In SunCast, open the address on the 3D map to see shadows from mapped buildings for any date and time, or use Street View Sun Path to see the sun’s path over the street. The free sun calculator on this site gives sun direction and times for the address.
What is the best time to view an apartment for sunlight?
It depends on the room. View bedrooms in the morning if morning light matters, living rooms during the hours you are usually home and balconies when you expect to use them.
