Reference · Dates

date.weekday

date.weekday(str) -> int

What it does

The day of the week of a date, as an int: 1 for Monday to 7 for Sunday (ISO 8601). A date-time gives the weekday of its date as written. For the name, use date.format with dddd or ddd.

Examples

print(date.weekday("2026-10-27"), date.weekday("2026-10-26"), date.weekday("2026-11-01"))print(date.format("2026-10-27", "dddd"))

2 1 7Tuesday

Edge cases

• Saturday and Sunday are 6 and 7, so weekday >= 6 is a weekend test.
• A date-time's weekday is that of its local date, not of the date in UTC.
• The calendar is the proleptic Gregorian one back to year 1: 1970-01-01 is a Thursday, 0001-01-01 a Monday.

print(["2026-10-30", "2026-10-31", "2026-11-01"] | map((d) => date.weekday(d) >= 6))print(date.weekday("2026-10-27T23:00:00-05:00"))print(date.weekday("1970-01-01"), date.weekday("0001-01-01"))

[false, true, true]24 1

Errors

Text that is not a date or a date-time, or any other value, is a runtime error, not an error value.

print(date.weekday("today"))

line 1: `date.weekday` expects a date or a date-time as argument 1, got "today"

Chaining

let names = ["Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"]print("2026-10-27" | date.weekday | (n) => names[n - 1])print(range(0, 7) | map((i) => date.add_days("2026-10-26", i)) | filter((d) => date.weekday(d) < 6) | len)

Tue5

See also

date.parts, date.format, date.add_days, date.days_between

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