the Monday before December 15th
Green Monday is an online shopping day similar to Cyber Monday, and it occurs on the last Monday when there are at least ten days prior to Christmas, which usually happens to be the second Monday in December. Online shoppers have historically wanted ten days between when they order gifts and Christmas, to ensure the gifts arrive in time. The day is like an online version of Super Saturday, where shoppers realize there isn't much time left to look for items, and that they must buy. As many retailers now offer guaranteed two-day shipping, the importance of getting all online shopping done by Green Monday has lessened. eBay came up with the name for the day, which has been in use since at least 2007. They called it Green Monday because of the extra revenue that the day brought in, and because online shopping may be more environmentally friendly than shopping at brick-and-mortar stores. It has become the largest shopping day in December, and in 2016 there were $1.6 billion in sales.
How to Observe Green Monday
In order to participate in the day, all you need to do is buy something online. Many of the major online retailers have web pages or specials dedicated to the day, although deals are not as extensive as those for Black Friday or Cyber Monday. If you choose to use a standard form of shipping instead of the two day which some retailers now offer, you should still receive your orders in time for Christmas.