It's about caps and gowns and speeches. To a slightly lesser extent, it's about students out for a meal on their parents' dime.
"Probably our busiest time... everyone's out for graduation dinner," Cosi Assistant Manager Lindsey Miller said.
Or perhaps a quick trip to get one last green-and-white T-shirt.
"We've seen a lot of parents come through," Student Book Store General Manager Howard Ballein said.
But for businesses like the SBS, it's a last hurrah of sorts.
"It's just numbers. It goes along with the students," Ballein said. "It's probably down 50 percent."
That is to say, down 50 percent during the summer versus the usual schoolyear hustle and bustle. You might expect a drop like that from a business so obviously dependent on students.
Still, how can a business possibly sustain such a dramatic drop in sales for three months?
"We know what to expect," Ballein said.
And SBS reacts by slimming staff slightly, but also using the time to get the store ready for the busy schoolyear just a few months away.
But the big drops aren't reserved for businesses with obvious direct connections to students.
"Probably like a third of what we make," Cosi Assistant Manger Lindsey Miller said.
That's what Miller expects this summer. And like SBS, Cosi is planning for it.
"Fewer people," Miller said. "We end up having to close earlier."
Of course, there are those niche businesses with a natural survival advantage for the long, hard East Lansing summer.
"The warm weather. School's out. The families have some extra time and they take their kids out to enjoy ice cream," Melting Moments Manager-on-Duty Brandon Fitzgerald said.
And for those businesses who do suffer, well, there's always an upside.
"In some ways, we appreciate a little slack," Ballein said. "Get my fishing pole out."