Amazon has set a shipping holiday for December 5th, 2018. However, please read the Seller Central News statement below as orders that are already marked with a December 5th ship date will still need to be shipped on time:
December 4, 2018
Shipping impact: USPS observing day of mourning December 5
USPS has notified all their customers that December 5, 2018, will be a national day of mourning for USPS in honor of former President George H.W. Bush. Due to this, USPS will not deliver or schedule pick-ups on December 5, 2018. To avoid a negative impact on customer deliveries, a shipping holiday has been set for December 5. This means that orders placed after your order cutoff time today can be shipped on December 6. For any orders with a ship date of Wednesday, December 5, please ship using alternate carriers to ensure you meet the delivery promise to customers.
More information can be found at the following link: http://about.usps.com/newsroom/statements/120318-usps-operating-status-national-day-of-mourning.htm.