With investors and analysts watching for slowing growth in a robust U.S. automotive market, January's results didn't provide strong evidence of a change in direction. 

Fiat Chrysler Automobiles (FCAU - Get Report) posted a 7% increase in unit sales, helped by steep discounts for an aging minivan model that's about to be replaced by the new Chrysler Pacifica minivan. 

General Motors (GM - Get Report) , the U.S. market leader, said that sales for the month were flat. Sales to fleets fell 23%, while retail sales to individuals rose 9% for the month. GM aims to reduce its proportion of fleet sales, which produce less profit than retail sales, to 20% of the total in the U.S, compared with 22% in 2015. 

At No. 2 for U.S. sales, Ford (F - Get Report) reported a 3% drop in vehicle sales for the month, including the top-selling F-Series pickups, which were off 5%. Ford's Lincoln luxury brand was up 8%.

Nissan (NSANY)  posted a 1.6% sales increase in U.S. sales in January. Toyota (TM - Get Report) , Honda (HMC - Get Report) , Hyundai (HYMLF) and other global manufacturers will be reporting monthly sales throughout the day. 

Economists were watching for any weakening in auto sales, which are big-ticket consumer items, that could foreshadow a weak first-quarter gross domestic product number for the period. Conversely, strong auto sales imply a high degree of confidence in continued employment and personal financial stability. 

Analysts had been expecting vehicle sales to get hurt in January because of poor weather. Following six straight years of annual sales increases by the industry, and record sales in 2015, consumers could be expected to pause in their vehicle replacement. Yet underlying demand seems strong, analysts said, pointing to a return to dealerships this month. 

"As expected, Winter Storm Jonas limited car sales from reaching their full potential," Jessica Caldwell, director of industry analysis at Edmunds.com, told Forbes. "But weather factors aside, this was still a pretty good month for car sales."

Doron Levin is the host of "In the Driver Seat," broadcast on SiriusXM Insight 121, Saturday at noon, encore Sunday at 9 a.m.

This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.