// Normal King's Day (April 27)
Carbon::parse('2021-04-27')->isKingsDay(); // true
// When April 27 is Sunday, celebrated on April 26
Carbon::parse('2025-04-26')->isKoningsdag(); // true
Carbon::parse('2025-04-27')->isKoningsdag(); // false
// Easter Sunday 2021
Carbon::parse('2021-04-04')->isEasterSunday(); // true
Carbon::parse('2021-04-04')->isPaaszondag(); // true
// Good Friday (the Friday before Easter)
Carbon::parse('2021-04-02')->isGoodFriday(); // true
Carbon::parse('2021-04-02')->isGoedeVrijdag(); // true
// Ascension Day (Thursday, 39 days after Easter)
Carbon::parse('2021-05-13')->isAscensionDay(); // true
Carbon::parse('2021-05-13')->isHemelvaart(); // true
// Pentecost (Sunday, 49 days after Easter)
Carbon::parse('2021-05-23')->isPentecost(); // true
Carbon::parse('2021-05-23')->isWhitsunday(); // true (alias)
Carbon::parse('2021-05-23')->isPinksterzondag(); // true (Dutch)
// Always a holiday (default)
'liberation_day' => true,
// Never a holiday
'liberation_day' => false,
// Only a holiday once every 5 years (2020, 2025, 2030, etc.)
'liberation_day' => 'once-every-5-years',
// With 'good_friday' => false in config
$date = Carbon::parse('2021-04-02');
$date->isHoliday(); // false (respects config - Good Friday disabled)
$date->isGoodFriday(); // true (checks the actual date - it IS Good Friday)