On which days do nations have their public holidays? I was wondering if nations tended to cluster along certain dates and time periods when it comes to public holidays. I made a calendar heatmap of the public holidays of the UN member states in 2022.
The 3 most celebrated public holidays, based on the gregorian calendar, are:
- New Year's Day (Jan 1st): public holiday in 156 countries.
- Christmas (Dec 25th): public holiday in 121 countries.
- Labor Day (May 1st): public holiday in 121 countries.

Sources:
- United Nations Member States (www.un.org/en/about-us/member-states)
- Holiday API (holidayapi.com)

Tools:
- Python for data collection
- Google BigQuery, SQL for data preparation and analysis.
- R, and RStudio for creating the chart.
- Pixelmator for the last visual touches.

P.S: new comment as first one didn't show up.