Sun Position.

Understanding sun position.

What does sun altitude mean?

Altitude is how high the sun sits above the horizon, measured in degrees. 0° means the sun is right on the horizon — this is sunrise or sunset. 90° would be directly overhead (only possible near the equator at noon). Negative numbers mean the sun is below the horizon, so it's nighttime. Altitude below −18° is called astronomical twilight — the sky is fully dark. Between −6° and 0° is civil twilight, when there's enough light to see outdoors without artificial lighting.

What is azimuth?

Azimuth is the compass direction of the sun, measured clockwise from north. North is 0°, east is 90°, south is 180°, and west is 270°. At sunrise the sun is roughly east (90°) and at sunset roughly west (270°) — but this varies significantly with latitude and season. Near the summer solstice at high latitudes, the sun can rise north of east (azimuth below 90°) and set north of west (azimuth above 270°), making for very long days.

Why does sunrise and sunset time vary by location?

The Earth is round, and your latitude and longitude determine when the sun crosses your local horizon. At the equator, days and nights are nearly equal year-round at about 12 hours each. At high latitudes like Scandinavia or Alaska, summer solstice can bring almost 24 hours of daylight while winter solstice brings nearly complete darkness. Your longitude determines how your clock time relates to solar time — which is why sunrise on the eastern edge of a time zone is noticeably earlier than on the western edge, despite both locations sharing the same clock.

What is day length and how is it calculated?

Day length is the time between sunrise and sunset — the number of hours the sun is above the horizon. It is calculated from the difference in the sun's position at your latitude on a given date. At the summer solstice (around 21 June in the Northern Hemisphere), day length is at its maximum; at the winter solstice (around 21 December) it is at its minimum. The equinoxes (around 20 March and 23 September) produce nearly equal day and night lengths everywhere on Earth.

How accurate are these calculations?

We use standard astronomical formulas based on Jean Meeus's Astronomical Algorithms, computed live in your browser with no server round-trip. Accuracy is within 1–2 minutes for sunrise and sunset times and about 0.5° for azimuth and altitude — more than sufficient for photography planning, navigation, and outdoor activities. Slight discrepancies from other sources are usually due to different atmospheric refraction models or terrain obstructions (a mountain can delay your observed sunrise by several minutes).

Is my location stored?

No. Your GPS coordinates are used only inside your browser to compute the sun's position. Nothing is ever sent to a server, and no location data is stored anywhere. Once the page has loaded, all calculations run offline — your location is never transmitted over the network.

How to Use Sun Position Data

Knowing exactly where the sun is in the sky unlocks a surprising range of practical applications — from planning the perfect photograph to figuring out which way your house faces, predicting shade patterns in a garden, or navigating in the wilderness without a compass.

Photography and videography

Professional outdoor photographers plan their shoots around the sun. The direction (azimuth) tells you where the light will come from at a given time, so you can position your subject to be front-lit, side-lit, or silhouetted depending on the effect you want. The altitude tells you how harsh or soft the light will be — high-altitude summer sun creates hard shadows and blown-out skies, while low-altitude sunrise and sunset light is warm, soft, and directional. Use the sun position tool the day before a shoot to scout exactly when the sun will be at the right angle for your location.

Drone operators also use sun position to plan flight paths that avoid lens flare and to calculate the best angle for aerial survey photography. A sun altitude below 30° is generally ideal for revealing surface texture and topographic detail in aerial shots.

Architecture and solar energy

Architects and passive solar designers use sun position data to determine how much sunlight will enter a building through south-facing windows (northern hemisphere) at different times of year. A sun path analysis tells you which rooms get morning sun versus afternoon sun, where shadows will fall in summer versus winter, and how to position overhangs and shades to block high summer sun while letting in low winter sun. Solar panel installers use the solar noon azimuth and average daily altitude to orient arrays for maximum annual yield.

Navigation without a compass

In a situation where you have no compass, the sun can provide a reasonably accurate directional reference. If you know the time and your approximate latitude, solar noon azimuth gives you the direction of south (Northern Hemisphere) or north (Southern Hemisphere). The classic watch method — aligning the hour hand with the sun and bisecting the angle between it and the 12 o'clock position — gives a rough north/south line. This tool gives you the precise solar azimuth in real time, which is more accurate than any rule-of-thumb method. Pair it with the Sun Compass for a combined direction and solar tracking view.

Gardening and outdoor planning

Gardeners use sun position data to plan where to plant shade-loving versus sun-loving plants, predict which parts of a garden will be in shadow at different times of day, and decide where to position a greenhouse or cold frame. Knowing that your patio gets full sun from 11am to 3pm in July but only from 12pm to 2pm in December, for example, can drive decisions about seating, shade structures, and planting. The day length reading is also useful for timing seasonal planting decisions and understanding when plants will naturally start to bolt or flower based on photoperiod.