Sunrise Calculator

About the Sunrise Calculator

Sunrise and sunset times depend on your geographic location, the date, and atmospheric refraction. At the equator, day length varies little throughout the year — about 12 hours year-round. But at higher latitudes, the difference is dramatic: London ranges from 8 hours in December to 16.5 hours in June. Beyond the Arctic/Antarctic circles, entire days of continuous sunlight (midnight sun) or darkness (polar night) occur.

The calculation involves solar declination (the sun's north-south position, ±23.45° over the year), the observer's latitude, and the equation of time (which accounts for orbital eccentricity and axial tilt). Atmospheric refraction lifts the apparent sun by about 0.83° at the horizon, adding a few minutes to visible daylight.

It gives sunrise, sunset, solar noon, day length, and civil twilight times for any location on Earth. The monthly table lets you see how daylight varies through the seasons — essential for planning outdoor activities, agriculture, photography, and solar energy systems.

When This Page Helps

Knowing sunrise and sunset is essential for photographers (golden hour), gardeners (frost timing), outdoor enthusiasts, pilots, and anyone planning activities around natural light. The monthly table reveals seasonal patterns at a glance.

How to Use the Inputs

1. Enter your latitude (positive for North, negative for South).
2. Enter your longitude (positive for East, negative for West).
3. Set your UTC time zone offset (e.g., -5 for EST, 0 for UTC).
4. Enter the day of year (1-365).
5. Review sunrise, sunset, day length, and monthly comparison.
6. Check for midnight sun or polar night at high latitudes.

Example Calculation

Tips & Best Practices

• Atmospheric refraction adds about 3-4 minutes of visible sunlight — sunrise appears earlier and sunset later than geometric predictions.
• Civil twilight begins/ends when the sun is 6° below the horizon — bright enough to see without artificial light.
• Day of year reference: Mar 20 = 79, Jun 21 = 172, Sep 22 = 265, Dec 21 = 355.
• At the equator, sunrise/sunset shift only ±30 minutes through the year. At 60° latitude, the shift is ±6 hours.

When To Use This Calculator

Calculate sunrise, sunset, day length, and civil twilight for any location and date. Includes monthly sunrise/sunset table and polar day/night detection. Use it when you need a repeatable calculation in the physics / general category and want the setup, result, and supporting values kept together. This is especially helpful when small input changes, unit choices, or rounding decisions can change the final number.

How To Check The Result

Start by confirming that the inputs match the formula shown on the page. Then compare the main output with the worked example and any secondary values shown by the calculator. If the result will be used in another calculation, keep extra precision until the final step and record the assumptions beside the number.

Practical Notes

Treat the result as a calculation aid rather than a substitute for context. For schoolwork, include the formula and substitution steps. For planning, technical, financial, or health-related decisions, verify important numbers against primary records, current rules, or a qualified professional before acting on them.

Frequently Asked Questions

• Why is sunset not exactly 12 hours after sunrise?

  It is approximately — sunrise to solar noon equals solar noon to sunset. But "12 hours from sunrise" is not meaningful; day length determines the gap between the two events.

• What is the midnight sun?

  When the sun never sets — occurs inside the Arctic/Antarctic circles during their respective summers. At the North Pole, the sun stays above the horizon for 6 months continuously.

• Why does solar noon differ from 12:00 PM?

  Time zones cover 15° of longitude but your location may be offset. Also, the equation of time adds up to ±16 minutes of correction from Earth's orbital mechanics.

• How accurate is this calculator?

  Within ±2 minutes for most locations. It uses the standard astronomical formulas but omits altitude correction and precise atmospheric refraction, which add ~1 minute of precision.

• Does altitude affect sunrise time?

  Yes — higher elevation means you can see farther over the horizon, advancing sunrise by a few minutes. This calculator assumes sea level.

• What is the equation of time?

  A correction (±16 minutes) for Earth's elliptical orbit and axial tilt that makes solar noon shift relative to clock noon through the year, forming the analemma pattern.