Inc. (NASDAQ:AMZN) made it official Wednesday: Its Prime Day shopping extravaganza — actually a two-day shopping spree — will return to the summertime.

The Seattle-based e-tailing giant said it will hold Prime Day on June 21 and 22, with members in 20 countries eligible to participate. Since its launch in 2015, Prime Day has been held in either June or July. The one exception was in 2020, when Amazon held Prime Day in October after the unprecedented online ordering surge during the first six months of the COVID-19 pandemic depleted Amazon’s inventories so heavily that it took until the fall to fully restock. Bloomberg News first reported Amazon’s decision to return the event to the summer months.

Last year’s shift effectively advanced the traditional holiday shopping and shipping cycle by 75 days as other retailers shifted their holiday promotions to mid-October to match the Prime Day promotions. Retailers are expected to follow Amazon’s lead again this year, and parcel delivery carriers can expect a midyear spike as a result. However, it should be an easier row to hoe for carriers and their retailer customers than it was last year, when Prime Day fed into the holiday shopping cycle with virtually no breathing room.

As for Amazon, the summertime Prime Day gives it a midyear peak with plenty of time to reload for the holiday season, said Brad Stone, senior executive editor at Bloomberg Technology and the author of a new book on the company called “Amazon Unbound.” Stone said he doesn’t believe that Amazon considered moving Prime Day permanently to the fall. Amazon did not respond to a request for comment on the issue.

Mark Magill, vice president of business development for OnTrac, a regional parcel delivery carrier whose eight-state Western network includes all of California, said the Prime Day shift should make it easier for carriers to plan their capacity requirements. However, Magill cautioned retailers that plan to start their holiday promotions in late November that delivery capacity during that time will be ultra-tight across the board.

Retailers, Magill said, “should just start sales at the beginning of November and continue them on so the carriers can actually deliver their orders on time.”

OnTrac, which still is running with capacity, will likely continue to onboard new customers through Sept. 1. Beyond that, procuring capacity will be a crapshoot, he said. Even those companies who sign up before that date will be in for a rude awakening if they plan to cram their deliveries within a three- to four-week period and expect all of them to be delivered on time, he said.