The sale features discounts on PC, Mac and Linux games of up to 95%, and users in the NEOGAF forum shared the information that the sale will already start on 19 June and will end 30 June.
Users on NEOGAF noticed that a Portuguese-language ad for online payment mechanism PaySafe was spotted advertising Steam sale dates of 19 June - 30 June, which is earlier than anticipated.
Eurogamer chimed in, reporting "Don't eat for eight days because on 19th June the Steam Summer Sale begins. It will run until 28th June with an encore that pushes it to 30th June."
The Summer Sale is usually Steam’s biggest of the year, offering huge discounts via daily deals and regular flash sales, along with publisher bundles and both short and long-term deals.
The team behind Steam, Valve, hasn't confirmed the summer sale yet, though it doesn't normally advertise the sales in advance, meaning they always tend to have an air of mystery about them.