Time and Date API
Time and Date (timeanddate.com) has 4 public methods: convert time between cities, count business days, get time in city and get sunrise and sunset. Each costs 1 credit per completed run (1¢ with pay as you go); failed runs are free.
Unofficial. Not affiliated with or endorsed by Time and Date.
Methods
4Converts a meeting time in one city to local times in other cities, with time zones and 09:00-17:00 working-hours status. Supports dates from 1970 to 2030; ambiguous clock-change times use the first occurrence.
Returns city, country, local date and time, weekday, time zone abbreviation, UTC offset, working-hours status, page link
Readtimeanddate.com/convert_time_between_citiesCounts weekdays between two dates, excluding nationwide public holidays or, optionally, public holidays in a state or province, from Time and Date's published holiday calendar.
Returns calendar days, weekend days, skipped holidays, business days, holiday calendar link
Readtimeanddate.com/count_business_daysGets the current local time, time zone, and next daylight saving change for a city listed on Time and Date. Add a state or country to distinguish cities with the same name.
Returns city, country, local date and time, time zone name and abbreviation, UTC offset, DST status, next DST change, link
Readtimeanddate.com/get_time_in_cityGets daily sunrise, sunset, solar noon, day length and civil twilight for a place from Time and Date, for one or more consecutive days. Times are local with UTC offset; days without sunrise or sunset are marked.
Returns place, per day: sunrise, sunset, solar noon, day length, civil twilight start/end, note, page URL
Readtimeanddate.com/get_sunrise_and_sunset