The markets are caught up in a May-September romance.

As the back half of May unfolds, a large majority of Wall Street play callers are projecting that September will be when the Federal Reserve finally will be able and willing to begin lifting short-term rates off the zero mark. And investors, for now, seem pretty blissful about this scenario.

Stocks were coaxed to a new all-time high for a brief moment late last week. And bonds have calmed down after a couple of weeks when yields scrambled higher. By the Wall Street Journal’s latest survey, some 73% of economists say September will bring the Fed’s “liftoff” rate hike, with 12% pegging June or July and the remaining 15% expecting nothing until the fourth quarter or beyond. Yet there’s a bit of a gap between what people are saying and how they’re behaving – not so unusual, perhaps, for May-September romances.

While the steady markets four months ahead of a scripted Fed action appears comforting, the expectations actually baked into the fixed-income markets is for the first Fed move to come in January, say Morgan Stanley researchers. Essentially, investors continue to anchor their views for monetary policy in persistently lackluster economic performance.

This entire bull market has relied heavily on “just the right amount of wrong,” as the sly Las Vegas casino ads say. In this case, that means just enough doubt about risks to the economic recovery – from global turmoil, labor-market slack, fiscal dysfunction, a strong dollar – to keep the Fed friendly even as the corporate sector thrives. The predominant bet as the week’s trading begins is clearly that this pattern will remain in place.

A year ago, a surprisingly weak first-quarter for U.S. growth was followed by a powerful bounce-back. In the second quarter of 2014, GDP jumped by nearly a 5% annualized rate. Following this year’s sluggish start, though, things are not pacing as well. More than halfway through the second quarter, U.S. growth might well fail to reach a 3% rate. And, as Wall Street Journal Fed reporter Jon Hilsenrath describes, a slow-growth economy remains ever vulnerable to being knocked off balance by relatively small shocks or setbacks.

Package it all together, and we have a pretty solid consensus built up behind the idea that bond yields will remain contained and stocks can keep grinding higher. Plausible, if not exactly insightful. This collective comfort with status quo policy and tepid growth probably means that any surprise will likely come in the direction of a more assertive Fed than a coddling one.

The Chicago Fed’s Charles Evans Monday reasserted his dovish stance that inflation should be allowed to run hotter for a while before any tightening move happens. Yet there remains a chance that Janet Yellen just wants to get this process started, perhaps to prevent financial markets from growing overconfident in their outlook and risk taking. Maybe she is preparing to prepare investors more carefully for a policy change. If nothing else, she means it when she says the Fed is truly data dependent.

In a world when the consensus can be off by two percentage points in a given quarter’s growth, that means a less predictable outlook, and perhaps more volatile market responses to incoming economic numbers.

This is why the week’s Fed speakers, including Yellen herself, and Wednesday’s release of the central bank minutes from the last meeting, will get more than their share of attention as corporate earnings slow and the summer news lull approaches.