Your deadline, not the carrier's
What has to be packed and shipped first?
Carrier holiday dates are recommendations, not promises. Use the current official cutoff for the exact service and destination, then move your own deadline earlier.
Deadline pages expire fast
Recheck the carrier source before buying postage and again near the shipping day. Weather, destination, service, international, military, and territory routes can differ.
Official starting point: USPS holiday shipping dates. If 2026 dates are not yet posted, wait for the official update rather than borrowing last year's table.