Regardless, the calendar says June, and you know what that means: It's time for the annual Steam Summer Sale.
Well, on the off-chance you don't know what it means, here's a primer. Every year Steam throws a bunch of sales, but the Summer Sale is typically the biggest of all. It's a great way to build up your PC gaming collection for 70- to 90-percent off the usual prices, though the longer you're in this the fewer deals you'll find to take advantage of.
This year's Summer Sale runs from today until June 21, and features the same standard format as previous Valve sales: Daily Deals, Flash Sales, and a host of assorted deals that'll run for the entire duration. Daily Deals refresh every day at 10 a.m. Pacific time and remain available for 48 hours. Flash Sales refresh every 12 hours, with the latter being voted on by Steam users.
Normally if you see a game as a Daily Deal or Flash Sale you should buy it--that's probably the lowest sale price you're going to see. Otherwise, conventional wisdom says wait until the last day of the sale before pulling the trigger. That way you make sure to get the best deal available.
Also important: Check other sites. Steam sales are legendary for a reason, but that "reason" gets less and less valid each year. Amazon is especially fond of undercutting Steam's prices during big sales.
Keep a tight hold on your wallet, don't buy games you're never going to play, and make sure to check the /r/GameDeals subreddit if you're feeling lost--the community over there does a fantastic job keeping track of deals every day. Together, we can fill your Steam backlog with useless games you never plan to play. Revelations 2012, anyone