Dec. 22 and 23 posted the highest year-over-year sales growth rates for the 2015 holiday shopping season, Custora data shows.

Faster shipping speeds fueled a last-minute holiday shopping rush to give Dec. 22 and 23 the highest online revenue growth year over year, a holiday report finds. A separate study shows Monday was the strongest day for online sales during the holiday season.

Web sales grew 22.8% on Dec. 22 and 32.1% on Dec. 23 compared with the same dates in 2014, according to Custora Inc., a provider of e-commerce marketing analytics that tracks retailer clients’ results. Custora, which did not release sales figures, bases its estimates on data from more than 200 online retailer clients representing over 500 million shoppers and $100 billion in e-commerce revenue.

Dec. 22 and 23 each accounted for 1.3% of revenue for the holiday season, defined as Nov. 1-Dec. 31. By comparison, online sales on Cyber Monday, the Monday after Thanksgiving, accounted for 6.3% of holiday sales revenue and grew 12.5% year over year, Custora says.

E-commerce revenue increased 12.1% over during the 2015 holiday season compared with the same period in 2014, according to Custora, with Cyber Monday and Black Friday (the Friday after Thanksgiving), as the highest-grossing holiday shopping days of the season. Custora’s estimate for holiday season growth is in line with the 12.7% growth estimated by Adobe Inc. based on its retailer clients’ sales and the 13% estimate from comScore Inc., which tracks the activity of a panel of online shoppers.

Custora says the biggest growth rates occurred just before Christmas, but the days leading up to and just after Thanksgiving ranked as the top revenue days for 2015 for Custora retailer clients, a change from 2014 when leading days were spread throughout the season, the report says. Those top days during the 2015 season, ranked in order by sales and with their share of holiday season revenue, are:

  • Cyber Monday, Nov. 30: 6.3%
  • Black Friday, Nov. 27: 5.2%
  • Sunday, Nov. 29: 3.0%
  • Saturday, Nov. 28: 2.8%
  • Tuesday, Nov. 24: 2.7%
  • Thanksgiving, Nov. 26: 2.4%
  • Wednesday, Nov. 25: 2.2%

“Last year Thanksgiving made a solid, though unsuccessful effort to break through as a leading holiday shopping day. In 2015, strong year-over-year growth of 10.7% helped Turkey Day earn one of those spots,” the report says.

“If the holiday shopping season is more of a marathon than a sprint, Thanksgiving weekend is where it catches its stride. For the full holiday weekend (Thanksgiving through Cyber Monday), revenue growth came in strong at 16.4% over 2014. During this time 19.8% of online revenue was generated for the holiday season,” Custora says. The month of December accounted for 44.8% of the holiday season’s revenue, the report says.

Stitch Labs, an inventory control vendor that helps retailers sell on online marketplaces, crunched holiday data in its “Holiday Retail Season Data Recap” report and found that transactions during Thanksgiving weekend (Nov. 26-Nov. 30) accounted for 12.6% of holiday season sales. Stitch Labs reviewed more than 10 million online orders from more than 3,000 small and medium-sized businesses. It also found:

  • Monday was the best day for online orders; Sunday was the worst.
  • Orders placed on branded websites on Cyber Monday had an average order value that was 2.4x higher than orders placed on Amazon.
  • Sales grew 65% on Cyber Monday for branded websites compared with 2014.
  • 78% of retailers offered some form of free shipping during the holiday season (Nov. 1-Dec. 31)
  • On Dec. 18, Free Shipping Day, 3 of 4 orders on Amazon shipped for free.
  • On Dec. 20, the peak free shipping day of the holiday season, 74% of online orders shipped for free.
  • Shoppers in Western and Mountain states spent 50% more per capita on consumer electronics than consumers in other regions.