How to use
- Choose a city or click Use my location, then pick a date.
- Drag the time slider to see altitude, azimuth, shadow direction and shadow length; enter an object height to get the shadow in the same unit.
- The sun path diagram compares the chosen day with the June solstice, the equinox and the December solstice.
- Below it, enter how far the building opposite rises above your window and the distance between them to estimate hours of direct sun.
Options explained
- Altitude
- The sun's angle above the horizon, from 0° at the horizon to 90° straight overhead. Calculated for the sun's centre without atmospheric refraction.
- Azimuth
- Compass direction measured clockwise from north, so east is 90°, south 180° and west 270°.
- Shadow length
- Shadow length as a multiple of the object's height, which is 1 ÷ tan(altitude). At 45° the shadow is as long as the object is tall.
- Window sunlight estimate
- Treats the building in front as an endless wall; the window gets sun when the sun's profile angle is higher than the top of that wall.
Why the winter sun is so low
The Earth’s axis is tilted by about 23.44°, so the latitude where the sun is overhead moves between the tropics during the year. The noon altitude is roughly 90° − your latitude + the sun’s declination. The table shows values from this tool for 2026:
| City | Latitude | June solstice noon | March equinox noon | December solstice noon |
|---|---|---|---|---|
| Singapore | 1.4°N | about 67.9° | about 88.3° | about 65.2° |
| Los Angeles | 34.1°N | about 79.4° | about 55.9° | about 32.5° |
| London | 51.5°N | about 61.9° | about 38.3° | about 15.1° |
| Sydney | 33.9°S | about 32.7° | about 56.5° | about 79.6° |
At the winter solstice the sun is lowest at noon, shadows are longest and buildings opposite block the most light, which is why winter is the season to check. In the northern hemisphere the summer sun rises in the north-east and sets in the north-west, while the winter sun rises in the south-east and sets in the south-west; the sun path chart shows the change.
For sunrise, sunset and twilight times, use the sunrise and sunset times tool.
Frequently asked questions
How far apart must buildings be for winter sun?
For sun around midday, the gap should be at least the height difference divided by the tangent of the winter-solstice noon altitude. At 40° latitude that altitude is about 26.6°, so the gap needs to be roughly twice the height difference, and more further from the equator. The estimate below shows the hours directly.
Can I rely on it when buying a home?
Treat it as a first check. It ignores the real shape of the buildings, gaps, trees and anything to the sides. For a planning decision, ask for a proper daylight and sunlight study.
Which way should solar panels face?
In the northern hemisphere usually due south, and in the southern hemisphere due north. A fixed tilt close to your latitude is a common starting point; steeper favours winter, flatter favours summer. The sun path chart shows how high the sun gets across the year.
Are times clock time or solar time?
Clock time in the city's time zone, including daylight saving time. Solar noon, when the sun is highest, is listed in the results and is often not exactly 12:00.
Privacy
This tool runs entirely in your browser. Your files and text are processed on your device and are never uploaded to our servers.