星期几查询工具
瞬间查出历史上或未来的任意一天究竟是星期几。
Which weekday is a date?
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计算原理
- The weekday is computed on the proleptic Gregorian calendar (the international standard) directly from the parsed date, never from a millisecond difference.
- Centuries are handled correctly: 1900 and 2100 are not leap years (divisible by 100 but not 400), and the engine’s unit tests pin those cases down.
- The ISO week number and the day-of-year are shown alongside, since the three answers usually travel together in planning and reporting.
使用提示
- Works across the full Gregorian range the engine supports, centuries back and forward.
- Dates from eras that used the Julian calendar historically will not match historical local usage; the Gregorian assumption is stated rather than hidden.
- Pair it with the Week Number tool for reporting weeks and the Business Days tool for working-day math.
相关工具
常见问题解答
How far back and forward does it work?
Across the full Gregorian calendar range supported by the engine, centuries back and forward, including leap-year exceptions like 1900 and 2100.
Is the Gregorian calendar assumed?
Yes, the proleptic Gregorian calendar, which is the international standard. Dates from eras using the Julian calendar will not match historical local usage.
Why does the weekday matter for planning?
Weekday drives business days, delivery windows, event scheduling, and recurring routines. The finder pairs with the Business Days and Week Number tools.