Consumer spending was unchanged in April vs. the previous month, according to this morning’s release of the government’s retail sales report. Last month’s flat performance follows a strong rise of 1.1% in March, which suggests that a degree of payback may explain April’s lackluster results. Even so, it’s hard to overlook the deceleration in growth in the year-over-year comparison. Whatever’s weighing on retail sales, it’s looking increasingly pervasive and beyond a mere seasonal bump.

Headline retail spending increased just 0.9% in April vs. the year-earlier level. That’s the slowest annual gain in nearly six years. The year-over-year advance is considerably higher when we strip out gasoline sales, although the 3.6% annual rise for spending ex-gas has been sliding lately too, posting the softest gain through last month in more than a year.

The spending data would be considerably more worrisome if payrolls stumbled in April. But as last week’s release shows, there was a dramatic rebound in private-sector employment last month. Meanwhile, initial jobless claims remain close to a 15-year low. For the moment, it’s not obvious that the soft retail data is infecting the rest of the economy. The optimistic view is that consumers have a new-found penchant for saving rather than spending. That could be a problem for the business cycle if it endures, but for now we’ll just have to wait for more data.

Nonetheless, any confidence about the US macro outlook is a bit more precarious in the wake of the ongoing deceleration in the year-over-year spending data. “It’s certainly is a disappointing report,” Guy Berger, an economist at RBS Securities, tells Bloomberg. “We are going to need to see some of these categories that were weak in April firm up in May and June.”

Accordingly, the next batch of economic reports will be critical for deciding if the recent deceleration in retail spending is noise or a darker signal. Based on the current data for the economy generally, there’s still a positive tailwind blowing, albeit one that’s turned softer later.

At the very least, the case for a solid Q2 snapback after the stall-speed data in Q1 still looks challenged. The Atlanta Fed’s May 5 nowcast for GDP growth in the second quarter was a tepid +0.8% and today’s sales figures certainly don’t offer any incentive to lift that forecast.

Meantime, while we’re waiting for more numbers, today’s release raises new questions about the timing of the first interest rate hike. “In terms of the Fed, the sluggish spending and economic growth performance will continue to argue for a later start to liftoff, essentially ruling out a mid-year hike,” says Millan Mulraine, deputy chief economist at TD Securities, via Reuters.