# DMY Date (dash-separated)

Key: `datetime.date.dmy_dash`

Day-Month-Year with dash separators and 4-digit year. Extremely common in EU informal data and Pandas examples. Ambiguous with mdy\_dash when day \<= 12.

Page: <https://meridian.online/docs/projects/finetype/types/datetime/date/dmy_dash>

Format: `%d-%m-%Y`

Samples: `15-01-2024`, `31-12-2023`, `01-06-2000`

## Written by

Each locale below writes this format with its CLDR date pattern at the styles named beside it.

`brx` short · `en` (MV) medium · `es` (CL) medium · `ia` short · `jv` short · `mi` short · `nl` short · `nl` (AW, BQ, CW, SR, SX) short · `rm` medium · `wo` short

## Background

### Origin

The Netherlands records dates in day–month–year order, with 31-12-1999 given as an example.[[1]](https://en.wikipedia.org/wiki/Date_and_time_notation_in_the_Netherlands) In Dutch date notation, dashes are typically used as separators, although slashes are used as well.[[1]](https://en.wikipedia.org/wiki/Date_and_time_notation_in_the_Netherlands) The List of date formats by country describes the Netherlands as using hyphens as in dd-mm-yyyy.[[2]](https://en.wikipedia.org/wiki/List_of_date_formats_by_country) Unicode's CLDR gives Dutch (nl) the short Gregorian date pattern dd-MM-y.[[3]](https://raw.githubusercontent.com/unicode-org/cldr-json/main/cldr-json/cldr-dates-full/main/nl/ca-gregorian.json) CLDR gives Chilean Spanish (es-CL) the medium Gregorian date pattern dd-MM-y.[[4]](https://raw.githubusercontent.com/unicode-org/cldr-json/main/cldr-json/cldr-dates-full/main/es-CL/ca-gregorian.json)

In India, DD-MM-YYYY and DD/MM/YYYY are described as the two predominant short forms of the Gregorian date.[[5]](https://en.wikipedia.org/wiki/Date_and_time_notation_in_India) Indian usage takes both the hyphen and the oblique as the separator between date fields.[[5]](https://en.wikipedia.org/wiki/Date_and_time_notation_in_India)

### Use

In Python's strptime format codes, %d is the day of the month as a zero-padded decimal number.[[6]](https://docs.python.org/3/library/datetime.html) In Python's strptime format codes, %m is the month as a zero-padded decimal number.[[6]](https://docs.python.org/3/library/datetime.html) In Python's strptime format codes, %Y is the year with century as a decimal number.[[6]](https://docs.python.org/3/library/datetime.html) DuckDB's strptime function throws an error on failure.[[7]](https://duckdb.org/docs/current/sql/functions/dateformat.html)

pandas.to\_datetime with dayfirst=True parses 10/11/12 as 2012-11-10.[[8]](https://pandas.pydata.org/docs/reference/api/pandas.to_datetime.html) The pandas documentation warns that dayfirst=True is not strict, but will prefer to parse with day first.[[8]](https://pandas.pydata.org/docs/reference/api/pandas.to_datetime.html) A value such as 05-06-2024 reads equally well as 5 June or 6 May, so a column where no day exceeds 12 cannot be told apart from month-first dashed dates by its values alone; look for the file's documentation or its country of origin before you commit to an order. (Meridian's view)

### Where you'll meet it

StatsWales's SW3 publishing platform accepts DD-MM-YYYY in data tables, with 01-01-2022 shown on the website as 1 January 2022.[[9]](https://publisher.stats.gov.wales/en-GB/guidance/Data-preparation-‐-New-datasets) SW3 also uses DD-MM-YYYY after a prefix for week-ending periods, so WE25-03-2022 is shown as week ending 25 March 2022.[[9]](https://publisher.stats.gov.wales/en-GB/guidance/Data-preparation-‐-New-datasets)

## Sources

1. [Date and time notation in the Netherlands](https://en.wikipedia.org/wiki/Date_and_time_notation_in_the_Netherlands) — secondary source
2. [List of date formats by country](https://en.wikipedia.org/wiki/List_of_date_formats_by_country) — secondary source
3. [ca-gregorian.json](https://raw.githubusercontent.com/unicode-org/cldr-json/main/cldr-json/cldr-dates-full/main/nl/ca-gregorian.json) — documentation
4. [ca-gregorian.json (es-CL)](https://raw.githubusercontent.com/unicode-org/cldr-json/main/cldr-json/cldr-dates-full/main/es-CL/ca-gregorian.json) — documentation
5. [Date and time notation in India](https://en.wikipedia.org/wiki/Date_and_time_notation_in_India) — secondary source
6. [datetime — Basic date and time types](https://docs.python.org/3/library/datetime.html) — documentation
7. [Date Format Functions](https://duckdb.org/docs/current/sql/functions/dateformat.html) — documentation
8. [pandas.to\_datetime](https://pandas.pydata.org/docs/reference/api/pandas.to_datetime.html) — documentation
9. [Data preparation: New datasets \| StatsWales](https://publisher.stats.gov.wales/en-GB/guidance/Data-preparation-‐-New-datasets) — organisation