Despite a series of economy data points that would seem to indicate that US growth has been slowing, investors may be waiting before they get worried. But if data comes in weak over the next two weeks, the wait could be over.

"This week's going to be an interesting one, because the economic data that's come out has been a little goofy, and yet the market just keeps pushing higher here," said Brian Stutland of the Stutland Volatility Group.

Indeed, the booked only a slight loss in the past week, despite the fact that several important economic numbers have fallen short of expectations.

Existing home sales in January were nearly nonexistent, with the Friday-released number missing expectations and coming in at an 18-month low. A similarly bad housing number came on Wednesday, when the Commerce Department reported that housing starts fell 16 percent in January.

On Tuesday, the Philadelphia Fed manufacturing index came in at negative 7.3, indicating worsening conditions as if fell far short of estimates. Tuesday's Empire State manufacturing survey also disappointed.

Bad economic news was even reflected in earnings, when Wal-Mart, the world's largest retailer, reported that same store sales fell 0.4 percent, and full-year guidance came in below expectations.

(Read more: What's eating Wal-Mart? Issues pile up for discount giant)

All of this negative news has besieged investors already wary after the last two jobs reports, which have shown job growth coming in sharply below expectations for both December and January.

What remains unclear is just how much of this bad news is due to the spate of bad winter weather, rather than an actual slowing of growth. But as data comes in over the next two weeks, that question should be answered.

"Weekly jobless claims will be important to watch, because you can't blame that on the weather," said Peter Boockvar, chief market analyst at the Lindsey Group, referring to the employment number that will be released on Thursday morning.

(Read more: Winter of discontent: Weather becomes economy's free pass)

He will also be watching the Chicago Purchasing Managers Index, which will be released Friday.

"We'll see if it confirms the weakness in the New York and Philadelphia numbers," Boockvar told CNBC.com.

In the following week, the February ISM manufacturing index and employment report should both draw unusual investor interest, as they will indicate how the economy performed this month.

In the meantime, economists are divided.

While Boockvar said that "this is deeper than the weather, but the weather may have enhanced any softness," Deutsche Bank chief US economist Joseph LaVorgna argued that "weather may impede economic activity in the short run, but it is unlikely to actually diminish demand—as a result, significant pent-up demand could result in a late-quarter surge in activity."

The question is whether the economy is simply in the grips of a chilly breeze or has actually caught a cold. And any incoming data will take on a special importance as investors rush to make that diagnosis.

—By CNBC's Alex Rosenberg. Follow him on Twitter: @CNBCAlex.

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