Week 53, 2026

Week 53 of 2026 runs from Monday, December 28, 2026 to Sunday, January 3, 2027.

ISO notation: 2026-W53
Start date: 2026-12-28
End date: 2027-01-03
All days: Monday 2026-12-28, Tuesday 2026-12-29, Wednesday 2026-12-30, Thursday 2026-12-31, Friday 2027-01-01, Saturday 2027-01-02, Sunday 2027-01-03
Previous week: Week 52, 2026
Next week: Week 1, 2027
API example: /api/week-to-date?year=2026&week=53&system=iso
Calendar export: /api/ics/week?year=2026&week=53&system=iso

Export Week 53

Download Week 53 as an all-day calendar event, or copy the JSON response for apps and automations.

{
  "year": 2026,
  "week": 53,
  "system": "iso",
  "isoWeek": "2026-W53",
  "weekStarts": "2026-12-28",
  "weekEnds": "2027-01-03",
  "days": [
    {
      "date": "2026-12-28",
      "weekday": 1,
      "name": "Monday",
      "isWeekend": false
    },
    {
      "date": "2026-12-29",
      "weekday": 2,
      "name": "Tuesday",
      "isWeekend": false
    },
    {
      "date": "2026-12-30",
      "weekday": 3,
      "name": "Wednesday",
      "isWeekend": false
    },
    {
      "date": "2026-12-31",
      "weekday": 4,
      "name": "Thursday",
      "isWeekend": false
    },
    {
      "date": "2027-01-01",
      "weekday": 5,
      "name": "Friday",
      "isWeekend": false
    },
    {
      "date": "2027-01-02",
      "weekday": 6,
      "name": "Saturday",
      "isWeekend": true
    },
    {
      "date": "2027-01-03",
      "weekday": 7,
      "name": "Sunday",
      "isWeekend": true
    }
  ]
}

Why 2026 has Week 53

An ISO year has 53 weeks when January 1 is a Thursday, or when a leap year starts on Wednesday. 2026 starts on Thursday, so it has a 53rd ISO week.