Summer doesn't actually begin until later this month, but The Witcher developer CD Projekt Red's GOG.com on Wednesday launched its annual Summer Sale. Free games, daily bundles, and more will take place through the Summer Sale, which runs today through June 21.

In addition to the standard discounts on games, GOG shoppers have a chance to score up to three free games during the sale period.

Spend more than $1 during the Summer Sale and you'll receive a free copy of SimCity 2000; spend at least $20 and you'll unlock S.T.A.L.K.E.R.: Clear Sky; spend more than $50 and you'll get a free copy of Xenonauts.

New deals for GOG's Summer Sale will appear on the site every 12 hours--more than 100 discounts will be available every day. Altogether, GOG more than 700 games will be marked down during the sale period by as much as 90 percent.

GOG kicks things off with deals on The Witcher 3: Wild Hunt (10 percent off), Lichdon Battlemage (87 percent off), and Jade Empire (80 percent off). A variety of bundles, including the Lucasfilm Adventures collection (Monkey Island, Sam & Max, and more) will be available for 66 percent off.

Head to GOG's website to see all the deals. As always, all games are completely DRM-free.

GOG isn't the only online retailer with plans for a summer sale. Just last week, the dates for Valve's annual summer sale leaked, suggesting the event would kick off on June 11, meaning it would overlap with GOG's.