It looks like someone has leaked the date of the Steam Summer Sale despite the image explicitly saying not to, but that’s not really our concern.
Posted by Reddit user MrFreemanBBQ, the dates for the summer sale are from June 23rd to July 4th. Of course, this information may not necessarily be true, however last year the summer sale dates were leaked in pretty much the same way.
We imagine most people will be reluctant to spend any money on Steam when they know a sale is coming, which is most likely why Valve wanted publishers/developers to keep quiet about the summer sale dates. Prior to only a few years ago, this was never a real problem as only big name publishers would deal with their games on Steam. With the rise of indie games, this information is almost guaranteed to leak, especially in this manner where the chances of being caught are incredibly low.
You’ll have just over a month to start saving your money!