SunriseTime is only useful if people can understand where the numbers come from.

Solar calculations

SunriseTime uses SunCalc-based solar calculations aligned with NOAA-style solar-position standards to derive sunrise, sunset, solar noon, twilight, and golden hour timing from latitude, longitude, and date.

• Sunrise and sunset are calculated per city coordinate pair.
• Golden hour windows are derived from the same daily solar events.
• Displayed times are formatted in the city's local timezone.

Moon data

Moon phase names, illumination, and moonrise or moonset estimates are generated from the same astronomy library stack used in the live city pages.

• Phase labels are mapped from the current lunar fraction.
• Illumination is rounded for readability.
• Moon details are presented as planning aids, not observatory-grade forecasts.

Prayer-time calculations

The current public SunriseTime experience uses the Muslim World League (MWL) convention for Fajr and Isha, with the Standard (Shafi'i) method for Asr.

• Fajr is calculated at 18 degrees below the horizon.
• Isha is calculated at 17 degrees below the horizon.
• Asr uses the standard shadow-length convention in the current public interface.

City directory

The public index currently covers 500 major cities. The list is curated from a GeoNames-based seed so the highest-demand locations are easy to browse and search first.

• Each city stores a canonical slug, country metadata, timezone, coordinates, and search aliases.
• Administrative region labels are used when a city needs stronger disambiguation in search or UI.
• Regional hubs group cities for easier comparison and deeper internal linking.
• The indexed directory can expand as coverage priorities change.

How updates work

• City pages are recalculated from the site's current build and utility layer.
• When content, city coverage, or calculation details change, SunriseTime should be rebuilt so pages stay aligned.
• Methodology and policy pages should be updated whenever the live product meaningfully changes.

Known limitations

• Displayed results are planning tools, not legal, navigational, or religious authority.
• Weather, terrain, skyline obstruction, and local observation conditions are not reflected in the raw timing output.
• Prayer-time preferences are not yet selectable in the current public interface.