How to read the month
Green, blue, clay, and grey mean different closures.
A pale green day is open on both calendars. Blue means only the first country is closed. Clay means only the second country is closed. Grey means both are closed, which covers ordinary weekends and shared holidays.
April 2026, United States against England and Wales: there is no US federal holiday. The UK is closed on 3 April and 6 April. Those two weekdays are clay if the UK is the second country. Common open days: 20. The arithmetic is on worked example.
The list under the grid names the holiday. “Weekend” is its own reason. A manual date says it was added by you.