Floating vs. fixed holidays: here’s the short version. Fixed holidays land on the same calendar date every year (think July 4). Floating holidays are anchored to a weekday pattern, such as the “second Sunday in May” or the “fourth Thursday in November,” which makes their date shift year to year. Understanding these rules helps you calculate dates quickly, automate calendars, and plan operations with fewer surprises.

What Do We Mean by “Floating” and “Fixed” Holidays?

Fixed-date holidays occur on a specific day and month each year. Examples include:

• New Year’s Day — January 1
• Independence Day (US) — July 4
• Veterans Day (US) — November 11
• Christmas Day — December 25

Floating holidays follow a weekday rule, not a fixed date. Their actual date changes annually, but the pattern stays the same. Familiar examples include:

• Thanksgiving (US) — fourth Thursday in November
• Mother’s Day (US) — second Sunday in May
• Memorial Day (US) — last Monday in May
• Labor Day (US) — first Monday in September
• Father’s Day (US) — third Sunday in June
• Martin Luther King Jr. Day (US) — third Monday in January
• Presidents Day (US) — third Monday in February
• Columbus Day/Indigenous Peoples’ Day (US) — second Monday in October

Outside the US, you’ll see similar patterns: Canada’s Thanksgiving (second Monday in October), the UK’s Spring Bank Holiday (last Monday in May), and many “bank holidays” that deliberately align to Mondays.

Why Do Some Dates Move Every Year?

Floating holidays are designed to keep observances attached to a desired weekday experience—like a long weekend, a Sunday gathering, or a reliable Monday closure—rather than a fixed calendar date. Lawmakers and institutions often use weekday rules to:

• Guarantee long weekends and predictable business closures
• Reduce midweek disruptions
• Standardize observance across years for work, school, and travel
• Create consistent volunteer, memorial, or family patterns

Historically in the US, the 1968 Uniform Monday Holiday Act shifted several federal observances to Monday to support consistency and economic activity tied to three-day weekends.

Common Weekday Patterns That Create Floating Holidays

The “Nth Weekday of Month” Rule

This is the most common pattern for civil holidays:

• US Thanksgiving: fourth Thursday in November
• Mother’s Day (US): second Sunday in May
• Father’s Day (US): third Sunday in June
• MLK Day: third Monday in January
• Presidents Day: third Monday in February
• Labor Day (US): first Monday in September

Because months start on different weekdays each year, the “nth” weekday falls on a different date. For example, the fourth Thursday in November can be as early as November 22 or as late as November 28.

The “Last Weekday of Month” Rule

Another popular rule anchors a holiday to the last occurrence of a weekday in a month:

• Memorial Day (US): last Monday in May
• UK Spring Bank Holiday: last Monday in May

This guarantees proximity to month-end and often creates a long weekend without pinning to a single date.

“Nearest Weekday to Date” and Other Variants

Some observances move to create a convenient weekday when a fixed date falls on a weekend. This is common in observance rules (e.g., if a fixed holiday lands on Sunday, it’s observed on Monday). These are not floating holidays per se, but they affect closures:

• US federal observance rules: if a holiday falls on Saturday, it’s typically observed on Friday; if Sunday, observed on Monday (5 U.S.C. 6103).

Lunar and Astronomical Dependencies

Some religious holidays are moveable because they depend on lunar cycles or astronomical events (e.g., Easter in the Gregorian calendar, Ramadan in the Islamic lunar calendar). While not civil holidays by default, they influence school schedules, global teams, and retail planning. They follow different algorithms than weekday-based civil holidays.

Quick Algorithms to Calculate Floating Holidays

You don’t need a full calendar engine to compute most weekday-based holidays. Here are practical formulas you can use.

Find the Nth Weekday of a Month

Goal: date for “nth WkDay in Month” (e.g., 4th Thursday in November).

1. Compute the weekday of the first of the month (0=Sunday…6=Saturday).
2. Let target be the weekday number of the desired day (e.g., Thursday=4 if Sunday=0).
3. Offset to first target weekday in the month: offset = (7 + target - firstWeekday) % 7.
4. Resulting date = 1 + offset + 7 × (n - 1).

Example (US Thanksgiving): fourth Thursday in November. If November 1 is a Saturday (6), target=Thursday (4), offset=(7+4-6)%7=5. Date=1+5+7×3=27 → Thanksgiving is Nov 27 that year.

Find the Last Weekday of a Month

Goal: date for “last WkDay in Month” (e.g., last Monday in May).

1. Find the last day number of the month (28–31, accounting for leap years).
2. Compute the weekday of that last day (0–6).
3. Let target be the weekday number you need.
4. Delta = (7 + lastWeekday - target) % 7.
5. Resulting date = lastDay - delta.

Example (Memorial Day): last Monday in May. If May 31 is a Friday (5) and Monday=1, delta=(7+5-1)%7=4 → Date=31-4=27 → Memorial Day is May 27 that year.

iCalendar Recurrence Rules (RRULE) You Can Copy

If you use Google Calendar, Outlook, or any iCal-compatible tool, these patterns automate floating holidays:

• US Thanksgiving: FREQ=YEARLY;BYMONTH=11;BYDAY=TH;BYSETPOS=4
• Mother’s Day (US): FREQ=YEARLY;BYMONTH=5;BYDAY=SU;BYSETPOS=2
• Memorial Day (US): FREQ=YEARLY;BYMONTH=5;BYDAY=MO;BYSETPOS=-1
• Labor Day (US): FREQ=YEARLY;BYMONTH=9;BYDAY=MO;BYSETPOS=1
• Father’s Day (US): FREQ=YEARLY;BYMONTH=6;BYDAY=SU;BYSETPOS=3

Tip: BYSETPOS picks the nth match within the month, and negative values (e.g., -1) mean “last.”

Planning Implications: Why Floating vs. Fixed Holidays Matter

Understanding precisely when floating holidays fall unlocks better planning across operations, staffing, and communications.

Workforce and Scheduling

• Coverage planning: Monday-holiday patterns concentrate closures and overtime demand at predictable times.
• Shift swaps: Retail, hospitality, and healthcare see predictable spikes around long weekends.
• Meeting calendars: Vacation patterns cluster around Monday holidays; plan critical meetings mid-week and avoid holiday weeks.

Payroll and Compensation

• Payday collision: If payday falls on a holiday or weekend, processing and funding often move earlier.
• Overtime premiums: Floating holidays on Mondays influence overtime rules for the adjacent weekend.
• Observed vs. actual: If a fixed holiday lands on Sunday and is observed Monday, which day triggers premium pay? Define it in policy.

Retail, Travel, and Supply Chain

• Holiday shopping season length varies: Because US Thanksgiving moves, there are about 26–32 shopping days between Thanksgiving and Christmas, changing demand curves.
• Carrier schedules: Shippers and couriers adjust pickups/deliveries around floating Monday holidays; build in buffer days.
• Dynamic pricing: Flight and hotel rates spike near long weekends—publish travel policies and blackout dates early.

Communications and Marketing

• Campaign timing: Email and ad cadence should reflect long-weekend behavior and Sunday-centric events like Mother’s Day.
• Localized content: Canada’s Thanksgiving is in October; tailor messaging and promos by country.

Education and Government

• Academic calendars: Align midterms, breaks, and commencements around floating holidays to avoid conflicts.
• Public services: Libraries, courts, and transit shift schedules for Monday holidays—communicate early.

Examples: How Floating-Holidays Shift Year to Year

• US Thanksgiving: Always a Thursday, but date ranges from Nov 22 to Nov 28.
• Memorial Day: Always a Monday, but date could be May 25–31.
• Mother’s Day: Always a Sunday, date varies between May 8–14.

These windows are predictable once you know the rule. For example, if November 1 is a Friday, the Thursdays fall on the 7th, 14th, 21st, and 28th—so Thanksgiving will be Nov 28.

US Federal Holidays: Floating vs. Fixed (At a Glance)

As of today, there are 11 US federal holidays. Six are floating, five are fixed-date:

• Floating (weekday-based): MLK Day, Presidents Day, Memorial Day, Labor Day, Columbus/Indigenous Peoples’ Day, Thanksgiving Day.
• Fixed-date: New Year’s Day (Jan 1), Juneteenth (Jun 19), Independence Day (Jul 4), Veterans Day (Nov 11), Christmas Day (Dec 25).

Observed-date adjustments apply when fixed-date holidays land on weekends.

Global Variations and Notable Differences

• Canada: Thanksgiving is the second Monday in October; Family Day occurs on a Monday in February (exact week varies by province).
• UK: Many “bank holidays” anchor to Mondays; Spring Bank Holiday is the last Monday in May.
• Australia: Various states use Monday-anchored public holidays with local rules.
• Religious calendars: Moveable feasts (e.g., Easter) influence school terms and trading hours even where not official public holidays.

Pros and Cons: Floating vs. Fixed

Floating Holidays

• Pros: Predictable long weekends; fewer midweek disruptions; easier travel and event planning.
• Cons: Actual date changes can confuse communications; cross-border misalignment complicates global operations.

Fixed-Date Holidays

• Pros: Easy to remember and brand; cultural dates remain intact (e.g., historical anniversaries).
• Cons: Day-of-week drifts; midweek closures can disrupt business; observance rules add complexity.

Practical Tips for Teams and Individuals

• Automate with RRULES: Use iCalendar recurrence rules for floating holidays to eliminate manual updates.
• Publish early: Release next year’s holiday/observance calendar in Q3 to help partners and staff plan.
• Clarify “observed” vs. “actual”: Spell out which day controls pay, closures, and SLAs.
• Localize calendars: Maintain country- or state-specific variations; avoid one-size-fits-all invites.
• Model demand: Incorporate the variable Thanksgiving-to-Christmas window into revenue and staffing forecasts.

Worked Examples You Can Reuse

Calculate US Mother’s Day (Second Sunday in May)

1. Find weekday of May 1.
2. Target=Sunday.
3. Offset=(7 + target - weekday(May 1)) % 7.
4. Date=1 + offset + 7 × (2 - 1) → between May 8–14.

Calculate US Memorial Day (Last Monday in May)

1. Find weekday of May 31.
2. Delta=(7 + weekday(May 31) - Monday) % 7.
3. Date=31 - delta → between May 25–31.

Calculate US Thanksgiving (Fourth Thursday in November)

1. Find weekday of Nov 1.
2. Target=Thursday.
3. Offset=(7 + target - weekday(Nov 1)) % 7.
4. Date=1 + offset + 7 × 3 → between Nov 22–28.

Bottom Line

Floating vs. fixed holidays are governed by simple, consistent rules. Once you know the weekday pattern, you can compute dates, create bulletproof calendar rules, and prevent last-minute scrambles. Whether you’re planning payroll, campaigns, or a family reunion, using the formulas and RRULES above will keep your schedule clear—and your stakeholders grateful.

FAQ

Why do governments choose floating holidays instead of fixed dates?

Floating holidays tie observances to weekdays to standardize long weekends, reduce midweek disruptions, and simplify planning for businesses, schools, and travelers. It’s a policy choice to favor consistency of experience over a fixed anniversary date.

Are floating holidays the same as “personal floating days” in HR?

No. In HR, “floating holidays” often means personal paid days employees can take any time. In calendars, floating holidays are public observances tied to weekday rules (e.g., “third Monday”).

How do observed dates work when a fixed holiday lands on a weekend?

In the US federal system, if a holiday falls on Saturday it’s usually observed on Friday; if it falls on Sunday, it’s observed on Monday. State and private-sector policies can vary, so confirm local rules.

What’s the earliest and latest US Thanksgiving can occur?

Earliest is November 22; latest is November 28. This shifting creates 26–32 shopping days until Christmas, influencing retail and logistics planning.

What’s the easiest way to add floating holidays to my calendar?

Use iCalendar RRULES. For example, Memorial Day: FREQ=YEARLY;BYMONTH=5;BYDAY=MO;BYSETPOS=-1. Most calendar apps support this format.

Do other countries use weekday-based holidays?

Yes. Canada, the UK, Australia, and many others use Monday-anchored public holidays. The exact rules vary by country (and sometimes by region within a country).

Are religious holidays considered floating?

Many are considered moveable because they depend on lunar or astronomical calculations rather than a fixed date. They’re distinct from civil floating holidays but have major planning impacts in education and global business.