The polar vortex that blanketed big swaths of the U.S. with snow this winter is also giving cover to companies seeking to explain why earnings rose last quarter at the slowest pace in almost two years.

Freezing temperatures and mountains of snow in the first three months of 2014 kept shoppers indoors, grounded flights and made it harder for shippers to fill product orders. As a result, Macy’s Inc. shut 244 stores for at least part of January, Union Pacific Corp.’s trains ran 9 percent slower and Delta Air Lines Inc. canceled 8,000 flights in January and February.

Companies already blaming the weather for poor performance include FedEx Corp., General Motors Co. and McDonald’s Corp. More will probably attribute weakness to the cold, even in cases where management may bear part of the responsibility, said William Stone, chief investment officer of PNC Wealth Management in Philadelphia, which manages $128 billion.

“For many of these businesses there’s a true impact,” Stone said in a phone interview. “The skill is to separate how much of it really is the weather and how much is them taking some liberty to blame other execution problems on the weather.”

Earnings at Standard & Poor’s 500 Index companies rose an estimated 1.1 percent in the first quarter, according to analysts’ estimates compiled by Bloomberg, slower than the 8.8 percent increase in the previous three months and the lowest rate since the second quarter of 2012.

Investors will have to wait for second-quarter results to gauge whether the stumble was all weather related, said John Carey, a fund manager for Pioneer Investment Management, a Boston-based firm that manages $220 billion. For now, it’s safe to presume U.S. and European growth will drive profits in 2014.

“I’m not sure the first quarter is going to be indicative of the year as a whole,” Carey said.

Arctic Air

The bulge of arctic air that settled over the Midwest and Northeast swept in snowstorms that shuttered businesses and government offices, snarled highway traffic and canceled thousands of flights. Profits across industries sputtered as heating bills soared, construction projects halted and train tracks had to be cleared of snow measured in feet.

Some effects were obvious: U.S. auto sales dropped 3.1 percent in January as people stayed away from showroom floors amid snow and sub-zero temperatures. Others not so much: PetSmart Inc.’s sales of flea-and-tick products dropped because freezing temperatures kill the pests.

In addition to tempered car sales, Ford Motor Co. said in February the weather caused lost production of 7,500 vehicles. Ford is projected to report earnings per share of 31 cents, down from 41 cents in the first quarter last year. At GM, which is also grappling with a recall of 2.6 million cars after faulty ignition switches were linked to 13 deaths, earnings per share will decline to 51 cents, according to 14 analysts, from 67 cents a year earlier.

JPMorgan, Apple

FedEx, considered a bellwether of the U.S. economy because of the variety of goods it delivers, cut its 2014 profit forecast on March 19 after the weather grounded flights and slowed surface shipments.

JPMorgan Chase & Co. will kick off the earnings season on April 11 as the first company in the Dow Jones Industrial Average to report. The largest U.S. bank is expected to post first-quarter earnings per share of $1.43, according to the estimates of 28 analysts, lower than $1.57 a year ago.

Apple Inc., the biggest U.S. company by market value, will report earnings per share of $10.14, estimates from 45 analysts show. That tops $10.09 a year earlier and would mark the second straight quarter of earnings-per-share growth after declines in the previous four. Apple will report earnings April 23.

Stock Prices

Anemic earnings growth probably won’t affect stock prices because investors see the detrimental weather as temporary, said Jonathan Golub, chief U.S. market strategist at RBC Capital Markets LLC. The S&P 500 Index has risen 5 percent since the beginning of February even as earnings estimates have been adjusted lower and economic data has been sluggish.

“My gut tells me that the market is going to be extremely forgiving of companies as long as their weakness can be attributed to one-off, weather-related stuff,” Golub said.

Analysts have reduced their first-quarter profit growth estimates for S&P 500 companies from 5.2 percent at the beginning of the year. Estimates for 2014 earnings per share for the index were scaled back to $117.6 from $119.2 on Jan. 3.

Companies typically guide analysts’ estimates down as the quarter proceeds and then beat those expectations, said Jim Paulsen, chief investment strategist at Wells Capital Management Inc. in Minneapolis, which oversees about $360 billion. In the last four quarters, companies beat estimates 71 percent of the time or more.

“I don’t look at real strong numbers as much as I do them surpassing really reduced estimates,” Paulsen said. “At this point, the expectations are down so much we’re going to have a favorable surprise again.”

Shoppers Hibernated

Many U.S. retailers have said the weather took a toll on business as shoppers hibernated at home. Gap Inc., the biggest U.S. apparel-focused retailer, was forced to close more than 450 stores for at least one day in February, and sales at stores open at least a year were down 7 percent in that month. Macy’s Chief Executive Officer Terry Lundgren said at a conference on March 11 that January was “one of the most difficult months I’ve ever had in my career,” and that “February started off like here we go again.”

Some analysts caution that the bounce-back some retailers are predicting once the weather warms may not appear.

“I have seen many retailers hide behind the weather excuse,” said Rick Snyder, an analyst for Maxim Group LLC in New York who covers retailers including Macy’s and J.C. Penney Co.

Happy Few

Economic indicators also are blurred by the weather, leaving investors to concentrate on employment and confidence indexes to get a read on the economy rather than studying first- quarter earnings, Paulsen said. The Institute for Supply Management reported its February manufacturing index rose by 1.9 percentage points from January to 53.2, while its service industries’ index dropped to 51.6, the lowest level in four years. Federal Reserve Chair Janet Yellen said weather played “an important role” in weakening first-quarter activity.

Some companies welcomed frigid temperatures. Questar Corp., a Salt Lake City-based energy producer, is riding an increase of gas prices to a high of $6.49 per million British thermal units on Feb. 24 from a low last year of $3.05 on Jan. 2 spurred by homes and businesses consuming more fuel to stay warm. Questar is estimated to report earnings per share of 47 cents per share, the most in four years.

Besides Weather

There are other things to talk about besides the weather, said Mitchell Stapley, chief investment officer for ClearArc Capital, a Cincinnati-based fund that manages about $7 billion. Russia’s annexation of Ukraine’s Crimea region threatens to derail a rebound in Europe, he said.

“Europe was looking a lot better until Ukraine flared up,” he said.

Earnings for companies on Europe’s Stoxx 600 Index, which includes Nestle SA and Novartis AG, are expected to rise 9.1 percent this year after declining 3.7 percent in 2013, according to earnings estimates compiled by Bloomberg.

Weather, though, will be the main topic, Stapley said. Reports could be “noisy” as companies are tempted to rid other pending losses from their books while investors already are bracing for profit misses, he said.

“You know the first quarter is going to be kind of a throw away,” Stapley said. “If you want put anything through, take it now and get all the bad news out.”