Your SLA report shows a miss rate spike. You call your 3PL. They pull up their numbers and say they hit 97%. You show them your report showing 84%. Nobody’s lying. Nobody made a math error. You’re running different operating calendars and nobody synchronized them.

This happens more often than people realize, and it’s not a Q4 problem. It surfaces on MLK Day, on Juneteenth, on Presidents’ Day, on the day of your 3PL’s annual inventory count. Any time your system’s operating calendar and your 3PL’s actual operating calendar are out of sync, you’re measuring noise. Accountability conversations go nowhere. Real performance problems hide behind calendar artifacts.

Here’s what actually goes into a 3PL operating calendar, what the industry norms look like at each layer, and what to get explicit about before it shows up in your reports.

The Three Layers of a Business Day

Every 3PL is running an operating calendar with three distinct layers. Most brands and 3PLs only consciously think about the first one.

Layer 1: The Weekly Schedule

Most 3PLs run Monday through Friday. That’s usually right, but not always.

Mid-to-large 3PLs commonly add Saturday operations during Q4 peak (roughly October through December). Smaller boutique 3PLs rarely do. Some run six-day operations year-round. Some run five days but with a Friday afternoon cutoff that effectively makes Friday a non-ship day for orders arriving after 10am.

What to ask: Does your schedule change seasonally? What’s the latest cutoff time that guarantees same-day processing?

This layer is usually documented. It’s in the contract. The problems live in layers 2 and 3.

Layer 2: Holidays

There are 11 US federal holidays. Most brands assume their 3PL observes “the holidays.” In practice, which ones get treated as non-shipping days varies more than you’d expect.

The split that matters: which days are the carriers also closed? A 3PL can be fully staffed and still unable to ship a single order if UPS and FedEx aren’t running pickups. The relevant question isn’t “is your warehouse open?” It’s “can an order placed today actually leave the building?”

The Big 6 (All Major Carriers Suspended)

New Year’s Day, Memorial Day, Independence Day, Labor Day, Thanksgiving, Christmas Day.

USPS, UPS, and FedEx all suspend operations on these six days. Nearly every US 3PL is non-operational regardless of whether warehouse staff is physically present. If your 3PL says they observe holidays, these six are guaranteed.

The Contested 5

MLK Day, Presidents’ Day, Juneteenth, Columbus Day, Veterans Day.

USPS is closed on all five. UPS and FedEx typically run normal operations. About half of mid-to-large 3PLs stay open. Whether orders actually ship depends on which carrier your 3PL uses and what their internal policy is.

These are worth asking about explicitly. “Do you ship on MLK Day?” gets you a real answer. “Do you observe federal holidays?” doesn’t.

The Edge Cases

Christmas Eve (Dec 24): Carriers operate but run early cutoffs and compressed sort runs. A 3PL that normally has a 3pm carrier handoff can’t effectively ship that day. Pickup gets moved to 11am or skipped. A 3PL with a morning cutoff is fine. This is arguably the highest-stakes SLA day of the year for ecommerce brands, and because it’s not a federal holiday, it often doesn’t appear in any formal schedule.

New Year’s Eve (Dec 31): Same dynamic. Carriers run compressed. Most 3PLs are open, but afternoon shipments are unreliable.

The week between Christmas and New Year’s (Dec 26–30): Not a holiday, but a meaningful number of 3PLs run skeleton crews through this stretch. Operations continue; throughput drops. It’s almost never in any contract. It shows up as a soft dip in January SLA reports and takes a few cycles to diagnose.

Observed vs. Actual Dates

Federal holidays that fall on a weekend shift to the nearest weekday for federal observation. When July 4 lands on a Sunday, the observed holiday is Monday July 5. Carriers follow the observed date. A system that only checks “is today July 4th?” gets this wrong. Saturday holidays shift to Friday; Sunday holidays shift to Monday.

One edge case: when January 1 falls on Saturday, the observed New Year’s Day lands on December 31 of the prior year. That one catches people off guard.

For an interactive version of this table with year picker and carrier filters, see the US Shipping Holiday Calendar. You can also subscribe to a calendar feed or pull the data into Google Sheets.

US Holiday Reference: What Most 3PLs Actually Do

Holiday	USPS	UPS	FedEx	Typical 3PL Status
New Year’s Day	Closed	Closed	Closed	Closed (Big 6)
MLK Day	Closed	Closed	Limited	Split: ask
Presidents’ Day	Closed	Open	Open	Split: ask
Memorial Day	Closed	Closed	Closed	Closed (Big 6)
Juneteenth	Closed	Open	Open	Split: ask
Independence Day	Closed	Closed	Closed	Closed (Big 6)
Labor Day	Closed	Closed	Closed	Closed (Big 6)
Columbus Day	Closed	Open	Open	Usually open
Veterans Day	Closed	Open	Open	Usually open
Thanksgiving	Closed	Closed	Closed	Closed (Big 6)
Christmas Day	Closed	Closed	Closed	Closed (Big 6)
Christmas Eve	Open	Open (early)	Open (early)	Open, but cutoff compressed
New Year’s Eve	Open	Open (early)	Open	Open, but cutoff compressed

Layer 3: Ad-Hoc Closures

These are one-off dates specific to a facility. They’re real, they’re common, and they almost never appear in any system.

Annual cycle counts: Most 3PLs shut down operations for one to two days each year for a full inventory count. Usually scheduled in January or February after peak. Nothing ships. In your SLA report, these days look like a hard drop in volume with no explanation.

Weather: A winter storm closes a Midwest facility. Operations pause. Orders queue. You find out when a customer calls.

Facility transitions: When a 3PL relocates to a new building, there’s a disruption window. Can be a day, can be a week.

Q4 receiving blackouts: Some 3PLs stop accepting new inventory during peak season (typically mid-October through mid-December). Not a closure, but a throughput constraint that affects how orders flow.

None of these are in your SLA contract. Good 3PLs communicate them in advance and flag the dates in any shared reporting so they don’t count against performance. Most don’t.

What It Actually Costs You

Here’s a realistic example. A brand has a same-day fulfillment SLA with a 2pm cutoff. Their 3PL uses USPS as the primary carrier. Their measurement system knows Monday through Friday but doesn’t account for USPS closures.

Order placed: Tuesday, January 20 at 10am (MLK Day).

The system calculates: same-day, expected to ship today.

Reality: the 3PL uses USPS as their primary carrier. USPS is closed on MLK Day. The order doesn’t leave the building until Wednesday.

The system flags this order as a same-day miss. The 3PL says they performed fine: they processed it same day, the carrier just couldn’t pick up. Both are looking at the same order and coming to different conclusions.

Now scale that to every order placed on any of the five “contested” holidays across the year, plus the Big 6, plus any ad-hoc closures. Your SLA report accumulates noise. Your 3PL stops trusting your numbers. Real problems get lost in the argument about calendar assumptions.

This isn’t hypothetical. It’s the standard state of affairs at brands tracking SLAs in spreadsheets or basic dashboards.

Questions to Ask Your 3PL

Get explicit answers to these before you build any SLA reporting:

Which of the 11 US federal holidays do you treat as non-shipping days?
Do you operate on Christmas Eve? What’s your carrier cutoff that day?
What’s your schedule the week of December 26 through 30?
Do you run Saturday operations? Year-round or only during peak?
When is your annual cycle count, and how do you handle SLA reporting around those days?
How do you notify clients about unplanned closures?
How are non-operating days reflected in your SLA performance reports?

If your 3PL can answer these cleanly, they’ve thought through their operating calendar. Vague answers on questions 1 through 3 usually mean the configuration doesn’t exist anywhere formal.

Why This Is Hard to Get Right

The weekly schedule is in the contract. That’s the easy part. The holiday list sits somewhere between industry norms and 3PL-specific policy, and nobody writes it down in a way that’s queryable. The ad-hoc closures aren’t documented anywhere until they happen.

When all three layers are correct and consistent between you and your 3PL, your SLA reports are meaningful. You can have real accountability conversations. When any one layer is assumed rather than explicitly configured, you get the disagreements described above: not because anyone is wrong, but because you’re measuring against different calendars.

The post on why calculating fulfillment time is harder than it looks covers the other side of this problem: timezones, cutoff times, what “shipped” actually means. Operating calendar issues compound everything in that post.

This is one of the things 3PL Pulse handles explicitly. For each provider, you configure which days they ship, which holidays they observe, and any one-off closed dates. The SLA math runs against that calendar automatically. When your calendar matches your 3PL’s reality, the numbers finally mean something.

Questions about how we handle this? Reach out.

The 3PL Operating Calendar: What Your SLA Math Assumes (and Shouldn't)