Sunrise & Sunset Calculator
Calculate Sunrise & Sunset
Formula
Hour angle = acos(−tan(lat) × tan(declination)) | Day length = 2 × hour angle / 15
Frequently Asked Questions
How accurate are these sunrise/sunset times?
These are approximate calculations based on simplified solar equations. Actual times may differ by 5–10 minutes due to atmospheric refraction, elevation, and the equation of time. For precise times, use astronomical almanac data.
What is solar declination?
Solar declination is the angle between the Sun and the celestial equator. It varies from +23.45° (summer solstice) to -23.45° (winter solstice) and determines day length at different latitudes.
Why are times shown in UTC?
UTC (Coordinated Universal Time) is used because local time zones vary. To convert to your local time, add or subtract your UTC offset (e.g., EST = UTC−5).
You may also need
A
Moon Phase Calculator
Free moon phase calculator. Find the moon phase, illumination percentage, and days until the next full or new moon for any date.
Science~
Day of the Week Calculator
Free day of the week calculator. Find what day any date falls on, plus the day of year and week number.
EverydayR
Time Zone Converter
Free time zone converter. Convert time between any two time zones. See what time it is in other cities around the world.
Conversion