December 13th, 2021
Green Monday is defined as the last Monday in December with at least 10 days prior to Christmas. Quite frequently it falls on the second Monday of December. It is quite the money-making day for many retailers, and often comes in as the second or third biggest online shopping day behind Cyber Monday.
Source: en.wikipedia.org/wiki/Green_Monday
Retailers can be urged to continue their holiday season advertising even further. Green Monday marketing strategies can push their profit margins even higher during the month of December.