{
  "id": "days-until-december",
  "version": "ae731bc27824",
  "status": "published",
  "name": "Days Until December",
  "question": "Days until December",
  "summary": "Counts the days from today, or any date you choose, to December 1, the first day of the next December, with its weekday and the time in weeks and months.",
  "category": "days",
  "subcategory": "countdowns",
  "url": "https://www.acalculator.org/days/days-until-december",
  "markdown": "https://www.acalculator.org/days/days-until-december.md",
  "kind": "function",
  "method": "Find the first December 1 on or after the start date, then count the days from the start date to it.",
  "assumptions": [
    "The count is to December 1, the first day of the month. During December, it counts to December 1 of the next year.",
    "The start date itself is not counted: from the day before, the count is 1; on the day itself, it is 0.",
    "Dates are calendar days with no time of day, so a time zone or a daylight-saving change never adds or loses a day.",
    "Start dates from January 1, 1900 to December 31, 2400 work."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "from": {
        "title": "Count from",
        "description": "The date to count from. Today, unless you change it.",
        "type": "string",
        "format": "date"
      }
    }
  },
  "outputs": {
    "days": {
      "label": "Days until December",
      "description": "Whole days from the start date to the next December 1; 0 on December 1 itself.",
      "format": "integer"
    },
    "date": {
      "label": "Date",
      "description": "The next December 1 on or after the start date.",
      "format": "date-long"
    },
    "weekday": {
      "label": "Day of the week",
      "description": "The weekday of that December 1.",
      "format": "text"
    },
    "weeks": {
      "label": "In weeks",
      "description": "The same number of days in weeks and days.",
      "format": "text"
    },
    "months": {
      "label": "In months and days",
      "description": "The time to that date in whole months, then days.",
      "format": "duration"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "from": "2026-09-30"
    },
    "outputs": {
      "days": 62,
      "date": "2026-12-01",
      "weekday": "Tuesday",
      "weeks": "8 weeks and 6 days",
      "months": {
        "years": 0,
        "months": 2,
        "days": 1
      }
    },
    "text": "From September 30, 2026, there are 62 days until December on Tuesday, December 1, 2026."
  },
  "examples": [
    {
      "given": {
        "from": "2026-09-28"
      },
      "expect": {
        "date": "2026-12-01",
        "days": 64,
        "weekday": "Tuesday"
      },
      "source": "U.S. Naval Observatory, Leap Years: the Gregorian leap year rule (https://aa.usno.navy.mil/faq/leap_years); Python 3 datetime: the next first of the month on or after the start date (docs/progress/WP-45/truth.py)"
    },
    {
      "given": {
        "from": "2026-12-01"
      },
      "expect": {
        "date": "2026-12-01",
        "days": 0,
        "weekday": "Tuesday"
      },
      "source": "U.S. Naval Observatory, Leap Years: the Gregorian leap year rule (https://aa.usno.navy.mil/faq/leap_years); Python 3 datetime: the next first of the month on or after the start date (docs/progress/WP-45/truth.py)"
    },
    {
      "given": {
        "from": "2026-12-02"
      },
      "expect": {
        "date": "2027-12-01",
        "days": 364,
        "weekday": "Wednesday"
      },
      "source": "U.S. Naval Observatory, Leap Years: the Gregorian leap year rule (https://aa.usno.navy.mil/faq/leap_years); Python 3 datetime: the next first of the month on or after the start date (docs/progress/WP-45/truth.py)"
    },
    {
      "given": {
        "from": "2028-02-29"
      },
      "expect": {
        "date": "2028-12-01",
        "days": 276,
        "weekday": "Friday"
      },
      "source": "U.S. Naval Observatory, Leap Years: the Gregorian leap year rule (https://aa.usno.navy.mil/faq/leap_years); Python 3 datetime: the next first of the month on or after the start date (docs/progress/WP-45/truth.py)"
    }
  ],
  "sources": [],
  "related": [
    "days-until-november",
    "days-until-january",
    "days-until",
    "days-between-dates"
  ],
  "changelog": []
}