Solar Altitude Calculator
Enter your location and local date/time to calculate the Sun's altitude angle above (or below) the horizon.
What is the altitude of the Sun?
The altitude of the Sun (also called the solar elevation angle) is the angle between the Sun and your local horizon. A value of 0° means the Sun is exactly on the horizon. Positive values mean it is above the horizon, and negative values mean it is below.
This value changes continuously through the day as Earth rotates, and through the year as Earth orbits the Sun. Your latitude, date, and local time are the key drivers.
How to use this calculator
- Enter your latitude and longitude.
- Select the local date and time you care about.
- Enter the UTC offset for that location and date.
- Click Calculate Altitude to get the Sun’s altitude and supporting values.
You can also click Use Current Date & Time to auto-fill the date/time and your browser’s UTC offset.
Understanding the result
Altitude angle
The main output is the solar altitude angle. For example:
- +65°: Sun is high in the sky (strong daylight).
- +10°: Sun is low, often near sunrise/sunset lighting.
- -8°: Sun is below the horizon (twilight or night).
Solar azimuth
Azimuth tells you compass direction (0° = North, 90° = East, 180° = South, 270° = West). This helps with solar panel alignment, photography planning, and shading studies.
Solar noon, sunrise, and sunset
The calculator also estimates local solar noon and sunrise/sunset times using a standard astronomical approximation. These values are useful for daylight planning, outdoor work, and energy modeling.
Why solar altitude matters
- Solar panel design: Estimate incident sunlight angles and optimize tilt.
- Architecture: Understand seasonal shading and passive heating/cooling.
- Photography & film: Predict golden hour and sun direction.
- Agriculture: Plan crop exposure and greenhouse management.
- Education: Visualize Earth–Sun geometry in a practical way.
Formula summary
This page uses a NOAA-style approximation based on:
- Day of year and fractional year angle
- Equation of time
- Solar declination
- Hour angle from true solar time
Solar altitude is then computed from latitude, declination, and hour angle using spherical trigonometry. For most practical uses, this method is accurate and fast.
Tips for best accuracy
- Use the correct UTC offset for the selected date (including daylight saving time if applicable).
- Double-check longitude sign: west is negative, east is positive.
- For high-precision scientific work, include atmospheric refraction and topographic horizon corrections.
Frequently asked questions
Is this the same as zenith angle?
Not exactly. Zenith angle is measured from straight up (the zenith), while altitude is measured from the horizon. They are complementary: Altitude = 90° − Zenith.
Can altitude be negative?
Yes. A negative altitude means the Sun is below the horizon.
Why is solar noon not always 12:00?
Because of longitude offset within time zones and the equation of time, the Sun usually crosses local meridian before or after 12:00 clock time.