Sunrise Sunset Calculator

Determine daily sunrise and sunset times for any location. Calculate daylight hours, twilight periods, and track seasonal light changes.

Date

Latitude

Longitude

Time Zone

About Sunrise Sunset Calculator

The Science Behind Solar Calculations

Ever wondered why sunrise times change throughout the year, or why the golden hour produces such magical light? The movement of the Sun across our sky follows precise mathematical patterns that humans have studied for millennia. Today, we can predict these solar events down to the second, thanks to our deep understanding of Earth's motion and modern computational methods.

Core Astronomical Concepts

Key Parameters:

Julian Date (JD): A continuous count of days since 4713 BCE
Solar Declination: The Sun's height above/below celestial equator
Hour Angle: Sun's east-west position relative to local meridian
Equation of Time: Natural variation between solar and clock time

Earth's Orbital Effects:

Elliptical orbit affects solar timing
23.5° axial tilt changes day length
Perihelion: January 3-5
Aphelion: July 3-5

Geographic Impact:

Latitude determines day length
Equator: ~12 hour days year-round
Poles: midnight sun and polar night
Local terrain affects visibility

Understanding Twilight Periods

Civil Twilight

Sun: 0° to -6° below horizon
Outdoor activities possible
Reading still possible outside
Venus becomes visible
Vivid, balanced colors

Nautical Twilight

Sun: -6° to -12° below horizon
Maritime navigation period
Horizon visible against stars
Mid-brightness stars visible
Artificial light needed

Astronomical Twilight

Sun: -12° to -18° below horizon
Darkest before true night
Faintest stars visible
Perfect for astronomy
Background light minimal

The Magic Hours of Photography

Golden Hour

After sunrise and before sunset
Warm, atmospheric lighting
Long, soft shadows
Perfect for landscapes
30-60 minutes duration
Varies with location/season

Blue Hour

Before sunrise, after sunset
Deep blue sky tones
Balanced artificial lighting
Ideal for cityscapes
20-30 minutes duration
Creates moody atmosphere

Real-World Applications

Agriculture

Optimal crop management
Greenhouse lighting
Frost risk assessment
Livestock management
Irrigation scheduling

Solar Energy

Peak efficiency periods
Panel tilt optimization
Maintenance planning
Energy yield prediction
Battery optimization

Architecture

Natural lighting design
Shadow impact studies
Window placement
Public space lighting
Seasonal shade planning

Frequently Asked Questions

How are sunrise and sunset times calculated?

Sunrise and sunset times are calculated using the sun's declination angle, the observer's latitude, and the equation of time. The sun rises when its center reaches 0.833 degrees below the horizon, accounting for atmospheric refraction and the sun's apparent diameter.

Why do sunrise and sunset times change throughout the year?

Earth's 23.5-degree axial tilt causes the sun's path across the sky to shift seasonally. During summer in the Northern Hemisphere, the sun follows a higher, longer arc producing later sunsets and earlier sunrises. The opposite occurs in winter.

What is civil twilight?

Civil twilight is the period when the sun is between 0 and 6 degrees below the horizon. There is enough natural light for most outdoor activities without artificial lighting. Nautical twilight extends to 12 degrees and astronomical twilight to 18 degrees below the horizon.

How does latitude affect day length?

Locations closer to the equator experience relatively consistent 12-hour days year-round. As latitude increases, seasonal variation grows dramatically. Above the Arctic or Antarctic circles, there are periods of 24-hour daylight in summer and 24-hour darkness in winter.

What is the equation of time?

The equation of time accounts for the difference between solar time and clock time, caused by Earth's elliptical orbit and axial tilt. This difference can be up to 16 minutes and affects the exact moment of solar noon, shifting sunrise and sunset times throughout the year.

Additional Resources

Sunrise - Wikipedia Sunset - Wikipedia Equation of Time - Wikipedia

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