In Canada, what is the official format for writing a date in numbers?

The custom and practice for writing dates in Canada owes something to conventions used in the UK and the USA and France. This mixture of conventions can give rise to confusion and so the government of Canada has specified the ISO 8601 format for all-numeric dates in official usage.

ISO 8601 is an international standard covering the worldwide exchange and communication of date and time-related data. It is maintained by the International Organization for Standardization (ISO) and was first published in 1988, with subsequent updates. The standard provides a well-defined, unambiguous method of representing calendar dates and times in worldwide communications, especially to avoid misinterpreting numeric dates and times when such data is transferred between countries with different conventions for writing numeric dates and times.

According to ISO 8601 calendar date representations are in the form YYYY-MM-DD, where YYYY indicates a four-digit year, MM indicates a two-digit month of the year (01 to 12) and DD indicates a two-digit day of that month (01 to 31). In some cases, the standard allows for the numeric date to be written without the separating hyphens. Accordingly the 19th of November 2024 would be written in numbers as 2024-11-19.