In this example, we use the Thanksgiving holiday:

• To get the fourth Thursday of November: GetDayOfWeekOccurrence(5, 4, Year(GetCurrentDateTimeUtc()), 11)
• To get the day after Thanksgiving (which may not always be the fourth Friday): AddDays(GetDayOfWeekOccurrence(5, 4, Year(GetCurrentDateTimeUtc()), 11), 1)
• To see if today is the same day as the specified day:
1. Save the specified day as a datetime variable like Task.thanksgiving.
2. Use a decision action and compare the today’s year, month, & day to Task.thanksgiving.  You might also want to check the hour/minutes if that’s needed.

For more details, download and import this Thanksgiving Schedule Example into Architect.

Holiday* Calculation
New Year’s Day MakeDateTime(Year(GetCurrentDateTimeUtc()), 1, 1)
Martin Luther King, Jr. Day GetDayOfWeekOccurrence(2, 3, Year(GetCurrentDateTimeUtc()), 1)
Groundhog Day MakeDateTime(Year(GetCurrentDateTimeUtc()), 2, 2)
President’s Day GetDayOfWeekOccurrence(2, 3, Year(GetCurrentDateTimeUtc()), 2)
Daylight saving’s starts GetDayOfWeekOccurrence(1, 2, Year(GetCurrentDateTimeUtc()), 3, 2, 0, 0)
Easter Cannot be calculated–use a list
Tax Day (approximate only–IRS can change the date) MakeDateTime(Year(GetCurrentDateTimeUtc()), 4, 15)
Mother’s Day GetDayOfWeekOccurrence(1, 2, Year(GetCurrentDateTimeUtc()), 5)
Memorial Day GetDayOfWeekOccurrence(2, -1, Year(GetCurrentDateTimeUtc()), 5)
Father’s Day GetDayOfWeekOccurrence(1, 3, Year(GetCurrentDateTimeUtc()), 6)
Independence Day  MakeDateTime(Year(GetCurrentDateTimeUtc()), 7, 4)
Labor Day GetDayOfWeekOccurrence(2, 1, Year(GetCurrentDateTimeUtc()), 9)
Halloween MakeDateTime(Year(GetCurrentDateTimeUtc()), 10, 31)
Daylight Saving’s Ends GetDayOfWeekOccurrence(1, 1, Year(GetCurrentDateTimeUtc()), 11, 2, 0, 0)
Election Day AddDays(GetDayOfWeekOccurrence(2, 1, Year(GetCurrentDateTimeUtc()), 11), 1)
Veteran’s Day MakeDateTime(Year(GetCurrentDateTimeUtc()), 11, 11)
Thanksgiving GetDayOfWeekOccurrence(5, 4, Year(GetCurrentDateTimeUtc()), 11)
Black Friday AddDays(GetDayOfWeekOccurrence(5, 4, Year(GetCurrentDateTimeUtc()), 11), 1)
Cyber Monday AddDays(GetDayOfWeekOccurrence(5, 4, Year(GetCurrentDateTimeUtc()), 11), 4)
Christmas Eve MakeDateTime(Year(GetCurrentDateTimeUtc()), 12, 24)
Christmas Day MakeDateTime(Year(GetCurrentDateTimeUtc()), 12, 25)
New Year’s Eve MakeDateTime(Year(GetCurrentDateTimeUtc()), 12, 31)

*Primarily US holiday examples