Sunset Calculator — Free Online Sunset Time Tool

How to Use the Sunset Calculator

1. Select a city or enter coordinates: Choose from 10 global city presets such as New York, London, Tokyo, or Sydney. Selecting a city automatically populates the latitude and longitude fields. For custom locations, manually enter coordinates. Latitude ranges from -90 (South Pole) to 90 (North Pole), and longitude from -180 (west) to 180 (east).
2. Choose your date: Select the date for the sunset calculation. The default is today. Choose any date to plan events like outdoor dinners, photography sessions, or evening hikes. The algorithm works accurately for dates within several centuries.
3. Read the sunset results: The main display shows the sunset time in approximate local time based on your longitude. The detailed results include UTC sunset time, civil dusk, golden hour start (approximately 60 minutes before sunset), and total day length for the chosen date.
4. Plan with local time estimates: The highlighted panel at the bottom converts all key times to approximate local time. The UTC offset is calculated from longitude. Verify against your actual timezone, especially if Daylight Saving Time is in effect or if your region uses a non-standard timezone.

Change the date to observe how sunset times shift across seasons. Comparing summer and winter solstice dates reveals the maximum annual range of sunset times for your location. Higher latitudes show dramatically larger seasonal swings.

Sunset Calculation Formula

Variables Explained

• Hour Angle: The angular distance the Earth rotates from solar noon to sunset. For sunset, this is added to solar noon (unlike sunrise, where it is subtracted). One hour of time equals 15 degrees of hour angle rotation.
• Latitude (lat): Your position north or south of the equator. Positive values for the Northern Hemisphere, negative for the Southern. Determines how the Sun's path arcs across the sky.
• Solar Declination (dec): The Sun's angular position relative to the celestial equator, varying from +23.44 degrees to -23.44 degrees throughout the year. This is the main driver of seasonal sunset time changes.
• -0.833 degrees: The standard altitude correction accounting for atmospheric refraction (0.567 degrees) and the Sun's semi-diameter (0.266 degrees). Sunset is defined as when the upper limb of the Sun touches the horizon.
• Solar Noon: The central reference point, calculated from the Julian Day, the equation of center, and the observer's longitude. Sunset is symmetrically offset from solar noon by the hour angle, just as sunrise is.
• Golden Hour: Approximately 60 minutes before sunset. Calculated by subtracting 60 minutes from the computed sunset time. Duration varies with latitude and season.

Step-by-Step Example

Calculate sunset for Paris (48.8566° N, 2.3522° E) on June 21, 2026 (summer solstice):

1. Date to Julian Day: JD for June 21, 2026
2. Solar declination near summer solstice: approximately +23.44 degrees
3. Calculate the hour angle with latitude 48.8566 and declination 23.44 degrees
4. The hour angle at the summer solstice for Paris is approximately 120 degrees
5. Sunset = Solar Noon + 120/360 days = Solar Noon + 8 hours
6. Solar noon in Paris on June 21 is approximately 13:50 local (CEST/UTC+2)
7. Sunset is approximately 21:50 local (CEST), one of the latest sunsets of the year

Paris at 48.86° N experiences nearly 16 hours of daylight at the summer solstice, with sunset not occurring until almost 10:00 PM local time. The golden hour begins around 8:50 PM.

Practical Examples

Example 1: Mike's Beach Wedding Ceremony

Mike and his partner are planning a sunset beach wedding in Los Angeles (34.0522° N, 118.2437° W) on September 20, 2026. They want the ceremony to culminate exactly as the Sun sets for dramatic photographs. Using the sunset calculator:

• Sunset: approximately 18:52 local time (PDT)
• Golden hour start: approximately 17:52 local time
• Civil dusk: approximately 19:18 local time
• Day length: approximately 12 hours 13 minutes

Mike schedules the ceremony to begin at 18:15, with vows at 18:40 to coincide with peak sunset colors. The photographer arrives at 17:45 to capture golden hour portraits before the ceremony. Post-ceremony photos continue through civil dusk until 19:18, when ambient light fades below usable levels.

Example 2: Priya's Evening Cycling Route

Priya cycles home from work in Mumbai (19.0760° N, 72.8777° E) and wants to ensure she finishes her route before dark. She checks sunset times for October through March, the months when daylight hours are shortest:

• October 15: sunset approximately 18:10, civil dusk approximately 18:33
• December 21 (solstice): sunset approximately 18:01, civil dusk approximately 18:24
• March 15: sunset approximately 18:38, civil dusk approximately 19:00

Priya discovers that Mumbai's equatorial proximity means sunset varies by only about 37 minutes across the entire year. She needs to leave her office by 17:15 during December to complete her 45-minute route before civil dusk. By March, she gains an extra half hour and can leave at 17:45. This minimal variation contrasts starkly with cities like London where winter sunset can be as early as 15:50.

Example 3: Tom's Outdoor Event Planning

Tom is organizing an outdoor corporate networking event in Dubai (25.2048° N, 55.2708° E) on November 10, 2026. The venue has limited artificial lighting, so he needs to ensure most activities happen before dark. Using the sunset calculator:

• Sunset: approximately 17:35 local time
• Civil dusk: approximately 17:58 local time
• Golden hour start: approximately 16:35 local time
• Day length: approximately 11 hours 4 minutes

Tom schedules the event from 15:00 to 18:30, planning the main networking reception during golden hour (16:35-17:35) when the outdoor lighting is most flattering. Catering and speeches wrap up by 17:30, and the final mingling period coincides with civil twilight until 18:00. He arranges for portable lighting to be activated at 17:45 as a precaution. Our current time calculator helps Tom coordinate with attendees arriving from different time zones.

Example 4: Elena's Astronomical Observation Planning

Elena is an amateur astronomer in Tokyo (35.6762° N, 139.6503° E) planning to observe the Orion Nebula on January 25, 2026. She needs to know when it will be dark enough for deep-sky observation. Using the sunset calculator:

• Sunset: approximately 16:57 local time (JST)
• Civil dusk: approximately 17:24 local time
• Day length: approximately 10 hours 13 minutes

Elena knows that deep-sky objects require astronomical twilight to end (Sun at -18 degrees) before the sky is truly dark. Using the sunset time as a starting reference and adding approximately 70-90 minutes, she estimates astronomical darkness begins around 18:30. She sets up her telescope by 18:00 and begins observations at 18:30 when the Orion constellation is well-placed above the southeastern horizon. For related dawn planning, the dawn calculator helps determine when to end the observing session.

Sunset Times Reference Table

Approximate local sunset times for the longest and shortest days. Times reflect Daylight Saving Time where applicable. Southern Hemisphere cities have reversed seasons.

Tips and Complete Guide

Understanding Twilight Phases After Sunset

After the Sun sets, darkness does not arrive instantly. Three distinct twilight phases follow sunset, each defined by the Sun's position below the horizon. Civil twilight (Sun 0° to -6°) lasts about 20-35 minutes and provides enough light for most outdoor activities. Nautical twilight (Sun -6° to -12°) follows, during which the horizon is still dimly visible and bright stars emerge. Astronomical twilight (Sun -12° to -18°) is the final phase, after which the sky reaches full darkness for telescope observations. At high latitudes during summer, astronomical twilight may never end, creating white nights where the sky never becomes fully dark.

The Green Flash Phenomenon

The green flash is a rare optical phenomenon that can occur at the very moment of sunset (or sunrise). As the last sliver of the Sun disappears below a clear, sharp horizon (usually over the ocean), a brief green or emerald-colored flash may be visible for 1-2 seconds. This occurs because the atmosphere acts as a prism, separating sunlight into its component colors. Green light is refracted more than red or orange, so it is the last color visible as the Sun dips below the horizon. Clear atmospheric conditions, a distant unobstructed horizon, and a stable atmosphere are necessary to observe this phenomenon.

Sunset Safety Considerations

While sunsets are beautiful to observe, several safety considerations apply. Never look directly at the Sun until it is very close to the horizon and clearly dimmed by atmospheric thickness — even a few minutes before sunset, direct viewing can cause eye damage. Drivers should be especially cautious during the period immediately before and after sunset when the Sun can be directly in the line of sight on east-west roads, causing severe glare. Hikers and outdoor enthusiasts should plan to return from trails well before civil dusk, as trail navigation becomes difficult in twilight. Our sunrise calculator helps plan the reverse timing for morning activities.

Sunset and Vitamin D Production

The Sun's UV radiation is responsible for triggering vitamin D production in human skin. However, effective vitamin D synthesis requires the Sun to be at least 30 degrees above the horizon, meaning the period near sunset (when the Sun is below 30 degrees) does not produce significant vitamin D. Understanding sunset times helps you plan outdoor time during the middle portion of the day when UV exposure is sufficient for vitamin D synthesis, typically between 10:00 AM and 3:00 PM local time. During winter at high latitudes, the Sun may never rise above 30 degrees, making vitamin D supplementation especially important.

Common Mistakes to Avoid

• Confusing golden hour timing: The golden hour starts approximately 60 minutes before sunset, not 60 minutes after. If sunset is at 19:00, golden hour begins around 18:00, not 20:00. Plan to be in position and ready well before the golden hour begins.
• Ignoring civil dusk for planning: Many people plan outdoor events until sunset, but there is still 20-35 minutes of usable light after sunset during civil twilight. Factor this buffer into event planning for post-sunset activities that do not require bright light.
• Forgetting Daylight Saving Time shifts: Our longitude-based local time does not account for DST. In regions observing DST, add one hour to the estimated local time during summer months. Always verify against your official local timezone.
• Assuming sunset direction is always west: The Sun only sets exactly due west on the equinoxes. In summer, it sets northwest (in the Northern Hemisphere), and in winter it sets southwest. The exact azimuth can be 30 or more degrees from due west at mid-latitudes.
• Not accounting for terrain: Mountains, hills, or buildings on the western horizon can cause the observed sunset to occur 10-30 minutes earlier than the calculated time. If precision is critical, scout your location beforehand to check the western horizon line.

Frequently Asked Questions