Credits

ExactClock is built on open data and open-source code. Thank you to everyone behind it.

Public holidays

Holiday data from date-holidays by commenthol and contributors, largely based on Wikipedia articles and official sources (list of sources). The data is licensed CC BY-SA 3.0. ExactClock adapts it – selecting, formatting and translating names (Simplified Chinese, English where no translation exists) – and offers the adapted holiday data under the same licence, on the website and in the Holiday API. The date-holidays code is ISC-licensed.

Sunrise and sunset

The calculation is ported from SunCalc by Vladimir Agafonkin (BSD 2-Clause licence):

Copyright (c) 2014, Vladimir Agafonkin
All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following
   disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following
   disclaimer in the documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Time zones and names

Time zones and daylight saving rules: the IANA Time Zone Database (public domain). Names of countries, months, weekdays and time zones: Unicode CLDR (© Unicode, Inc., Unicode License V3), both through the browser’s and Node.js’s built-in Intl.

Other

Easter dates use the anonymous Gregorian algorithm and Meeus’ Julian algorithm; week numbers follow ISO 8601. Optional random background photos come from Picsum Photos (images from Unsplash, Unsplash License).