What the calculator shows
Choose an airport or enter coordinates, a date, an observer elevation, and an IANA time zone. The calculator returns sunrise, sunset, civil dawn, civil dusk, solar noon, and the elapsed time between sunrise and sunset. Inputs stay in the URL so a location and date can be shared.
These are calculated solar events, not observations or current weather. The airport list uses the records available on this site. Choose Custom coordinates for a location that is not listed.
How to use the calculator
Select an airport to load its coordinates and field elevation. For a custom location, enter decimal latitude and longitude. North and east are positive. South and west are negative. Coordinates in degrees and decimal minutes must be converted to decimal degrees before entry.
Choose the calendar date and enter the time zone used to display the times. The default is UTC. Enter an IANA time-zone name such as America/Denver or Pacific/Honolulu to use local clock time and the correct daylight-saving offset for the selected date. The entered date is interpreted in that time zone, including when a solar event falls on a different UTC date. A time-zone abbreviation such as MST is not an IANA time-zone name.
Observer elevation is entered in feet above mean sea level. Airport choices fill this from the airport record. For a custom location, enter an elevation or leave it at zero. Elevation changes the modeled horizon, so the result can differ from a sunrise table calculated for a sea-level observer.
How the calculation works
The calculator uses the locally installed suncalc3 library. It evaluates solar events for the selected coordinates and observer elevation, then formats each event in the selected time zone. It checks adjacent UTC dates as well as the selected date so locations near the international date line still return events for the requested local calendar date.
Sunrise is the library's event for the Sun's upper edge appearing at the horizon. Sunset is the event for the Sun disappearing below the horizon. Civil dawn and civil dusk are the library's civil-twilight events. Daylight duration is the elapsed time from sunrise to sunset, rounded to the nearest minute. The result is not computed by subtracting clock values, which could be incorrect across a daylight-saving transition.
Worked example
For KAPA, Centennial Airport, on June 21, 2024, with the airport's listed elevation and the America/Denver time zone, the calculator returns sunrise at about 5:24 AM MDT and sunset at about 8:40 PM MDT. Civil dawn is about 4:51 AM MDT, civil dusk is about 9:13 PM MDT, and the calculated daylight interval is 15 hours 16 minutes. This is a reproducible model output, not a report of an observed sunrise.
Aviation use and limitations
Sunrise and sunset estimates can help organize a study schedule or review the daylight and twilight window around a planned activity. Civil twilight is also relevant to the definition of night in U.S. aviation regulations. Under 14 CFR 1.1, that definition uses the end of evening civil twilight and the beginning of morning civil twilight as published in the Air Almanac and converted to local time. This calculator does not reproduce the Air Almanac or determine whether a flight, logbook entry, or currency requirement meets a regulation.
The calculation assumes a clear, unobstructed horizon. It does not model terrain, buildings, trees, cloud, visibility, or a location-specific horizon profile. Observer elevation adjusts the modeled horizon, but airport elevation and coordinates can be incomplete or out of date. The page displays the airport dataset source and update date when an airport is selected.
At high latitudes, the Sun may not cross the horizon on a selected date. In that case, sunrise, sunset, and daylight duration can be unavailable. Civil twilight or solar noon may still occur. A missing sunrise or sunset is a geometric result, not a data-feed outage.
Common questions
Why is a time zone required?
Solar calculations produce absolute instants. The time zone converts each instant to a calendar date and clock time. UTC is the default because it avoids guessing the location's civil time zone. If local times are needed, enter the IANA time zone for the location.
Why does my result differ from another sunrise table?
Sources can use different observer elevations, event definitions, rounding, and time zones. This calculator uses the upper edge of the Sun for sunrise, the disappearance of the Sun for sunset, and the entered observer elevation. Compare like assumptions and confirm important times against an appropriate official source.
Can I use the result to decide if a flight is legal?
No. This is a training and reference estimate, not an operational decision tool. Regulatory definitions can specify an official source or method that differs from this model. Check current FAA publications, applicable regulations, and the aircraft POH or AFM.
What if the airport is not listed?
Choose Custom coordinates and enter the location's decimal latitude, longitude, elevation, and time zone. Custom values are saved in the URL just like airport selections.
Sources and methodology
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