What the calculation uses
Aletheia combines the coordinates and height you enter with an astronomical model, then applies the selected IANA time zone to each exact UTC event. The time zone does not determine the Sun’s position; it determines the local clock reading and calendar date.
Why actual results can differ
The model includes a standard approximation for atmospheric refraction and the apparent edge of the Sun. Weather, pressure, terrain, buildings, a non-level horizon, and imprecise coordinates can change what a person actually sees.
Polar and one-event dates
Near the poles, a civil date may have no sunrise, no sunset, or only one of those events. The calculator reports that condition directly instead of inventing a time.
Current civil-time boundary
Government time-zone rules can change. This tool uses the timezone data installed in the current browser and supports dates from 1970 through 2100. It is not a historical Events Timeline or a navigation and safety instrument.
Related tools
Use the Time Zone Converter for civil-time conversion or the World Clock for current time across selected zones.
Calculation version
Aletheia calculation 1.0.0; astronomical model astronomy-engine 2.1.19. Inputs stay in the browser and are not included in analytics.