https://en.wikipedia.org/wiki/Date_and_time_notation_in_Canada#:~:text=The%20Standards%20Council%20of%20Canada,formats%20often%20results%20in%20misinterpretation.
All-numeric dates
The Government of Canada recommends that all-numeric dates in both English and French use the YYYY-MM-DD format codified in ISO 8601.[10] The Standards Council of Canada also specifies this as the country's date format.[11][12]
The YYYY-MM-DD format is the only officially recommended method of writing a numeric date in Canada.[2] The presence of the DD/MM/YY (most of the world) and MM/DD/YY (American) formats often results in misinterpretation.
https://en.wikipedia.org/wiki/Date_and_time_notation_in_the_United_States
In the United States, dates are traditionally written in the "month-day-year" order, with neither increasing nor decreasing order of significance. This is called middle endian. This order is used in both the traditional all-numeric date (e.g., "1/21/22" or "01/21/2022") and the expanded form (e.g., "January 21, 2022"—usually spoken with the year as a cardinal number and the day as an ordinal number, e.g., "January twenty-first, twenty twenty two"), with the historical rationale that the year was often of lesser importance. The most commonly used separator in the all-numeric form is the slash (/), although the hyphen (-) and period (.) have also emerged in the all-numeric format recently due to globalization. The Chicago Manual of Style discourages writers from writing all-numeric dates, other than the year-month-date format advocated by ISO 8601, as it is not comprehensible to readers outside the United States.[5][6]
The day-month-year order has been increasing in usage since the early 1980s. The month is usually written as an abbreviated name, as in "19 Jul 1942" (sometimes with hyphens).[5] Many genealogical databases and the Modern Language Association citation style use this format. When filling in the Form I-94 cards and new customs declaration cards used for people entering the U.S., passengers are requested to write pertinent dates in the numeric "dd mm yy" format (e.g. "19 07 42"). Visas and passports issued by the U.S. State Department also use the day-month-year order for human-readable dates and year-month-day for all-numeric encoding, in compliance with the International Civil Aviation Organization's standards for machine-readable travel documents.[7][8]
The fully written "day-month-year" (e.g., 25 August 2006) in written American English is recommended by the Chicago Manual of Style for material that requires many full dates, as it does not require commas.[9] Most Americans still write "August 25, 2006" in informal documents. Speaking the "day month year" format is still somewhat rare, with the exception of holidays such as the Fourth of July.
The year-month-day order, such as the ISO 8601 "YYYY-MM-DD" notation is popular in computer applications because it reduces the amount of code needed to resolve and compute dates. It is also commonly used in software cases where there are many separately dated items, such as documents or media, because sorting alphabetically will automatically result in the content being listed chronologically.
Two U.S. standards mandate the use of year-month-day formats: ANSI INCITS 30-1997 (R2008); and NIST FIPS PUB 4-2 (FIPS PUB 4-2 withdrawn in United States 2008-09-02[10]), the earliest of which is traceable back to 1968. This order is also used within the Federal Aviation Administration and military because of the need to eliminate ambiguity.