There is something about the week after Labor Day that feels like a collective return to work. Children head back to school, football once again occupies the weekends, and the rhythms of summer give way to a calendar that suddenly feels much more consequential. Financial markets often experience a similar transition. After a relatively quiet summer in which investors seemed willing to look through a surprising amount of uncertainty, September arrives with a decidedly fuller syllabus. The economy remains resilient and corporate earnings have generally held up, but the comfortable assumption that the Federal Reserve would eventually ride to investors’ rescue has become harder to maintain. Chair Kevin Warsh used his first Jackson Hole address to emphasize that the Fed must be confident inflation is moving toward its 2% objective—and suggested policymakers still have “work to do” if it is not. Markets heard the message: expectations for tighter policy increased and Treasury yields moved higher following the speech. In other words, summer vacation is over, and monetary policy may once again be the toughest class on the schedule.

Of course, the Fed is hardly the only subject demanding investors’ attention. The war with Iran has now stretched beyond six months, and what initially looked like the sort of geopolitical shock markets might quickly digest has instead become a persistent source of uncertainty. Restrictions on traffic through the Strait of Hormuz remain an important constraint on global energy markets, while the expiration of the summer ceasefire has returned oil prices—and the possibility of renewed escalation—to center stage. Like a football team that spent the offseason drawing up its game plan only to discover that the opponent has changed formations, investors are being forced to reconsider how higher energy prices might interact with an already complicated inflation backdrop. That linkage matters: a prolonged geopolitical risk premium in oil could simultaneously pressure consumers, corporate margins and inflation, leaving the Fed with considerably less room to support growth. Markets became remarkably adept this summer at treating the war as background noise; autumn may test whether that complacency was justified.

And then there is November. With the midterm elections now just two months away, politics will increasingly compete with economics for investors’ attention. Control of Congress is closely contested, and the combination of inflation, the economy, energy prices and the Iran war is moving to the center of the campaign. Markets have historically learned to live with elections—and divided government is hardly an unfamiliar outcome—but the weeks leading into Election Day can nevertheless introduce another layer of uncertainty around fiscal policy, regulation and the broader direction of Washington. So, as we turn the page from summer to fall, investors might think of the coming months much the way students view the beginning of a new school year or football teams approach opening weekend: everyone starts with a clean notebook and an optimistic record, but the real tests are still ahead. The lesson of the summer was that markets can tolerate an extraordinary amount of uncertainty when growth and earnings remain supportive. The question for the fall is whether investors can continue looking past that uncertainty, once monetary policy, geopolitics, and politics are all back on the field at the same time.