NPD predicts that the back-to-school season–the second largest shopping season of the year–will charge up retail this summer, giving apparel sales a nice boost.

The back-to-school season is the second most important time in the retail calendar, behind the holiday season, says retail research and analysis organization, The NPD Group.

Similar to the holiday shopping season, back-to-school shopping is beginning earlier and lasting longer–this year, 28 percent of consumers told NPD that they plan to start earlier than they did last year. In 2016, across all industries, 20 percent of consumers began back-to-school shopping before May, with 8 percent completing their shopping during this early period. There were plenty of late-season shoppers too–14 percent of consumers didn't finish their school shopping until after October.

Three-quarters of back-to-school shoppers bought apparel for K-12 students during the 2016 shopping season. Apparel captured 24 percent of total back-to-school purchases in 2016, and this was even higher among K-12 (29 percent).

In the 2017 season, apparel is expected to have the second highest average spend, not far behind electronics. Almost 60 percent of consumers plan on spending more on apparel for the 2017-2018 school year.

"Despite the lack of passion for fashion among young people, these categories are important to back-to-school shoppers and spells opportunity that can expand beyond apparel and into the fashion of dorm décor," says Marshal Cohen, chief industry analyst, NPD.