This story has been updated from 10:49 am EST with additional Cyber Monday sales information.

NEW YORK (TheStreet) -- Will Cyber Monday sales make up for the disappointing sales numbers seen during the rest of the Thanksgiving weekend?

An estimated 131 million consumers are expected to shop online on Monday, up from 129 million who participated last year, according to the National Retail Federation, a trade organization representing the nation's largest retailers. Consumers increasingly prefer shopping online as opposed to shopping in stores over the holiday weekend.

More shoppers also plan to use their mobile devices this year. The NRF predicts that 24.8 million people, up 22% from 2012, plan to buy via their smartphone or tablet.

"We expect Cyber Monday to be bigger than ever," said NRF President and CEO Matthew Shay, in a press release on Sunday.

As for when they'll shop, 43.3% will pounce on Cyber Monday deals first thing in the morning. Another 19.3% will shop over their lunch hour and 33% will shop in the early afternoon, the NRF survey found.

As of 12 p.m. EST, Cyber Monday online sales were  up 21.4% in 2013 over the same period last year, according to the most recent data by IBM Digital Analytics Benchmark. Mobile traffic accounted for more than 31% of the Cyber Monday sales, up 58% from last year, the IBM data found. Mobile sales remained strong, reaching close to 18% of all online sales, IBM said.

The IBM Benchmark also found:

Smartphones Browse, Tablets Buy: Smartphones drove 20.7% of all online traffic compared to tablets at 10%, making it the browsing device of choice. When it comes to making the sale, tablets drove 11% of all online sales, almost twice that of smartphones, which accounted for 6.8%. Tablet users averaged $132.73 per order, versus smartphone users, who averaged $117.30 per order.

iOS vs. Android: As a percentage of total online sales, iOS users were more than four times higher than Android, driving 14.4% of sales vs. 3.4% for Android. On average, iOS users spent $125.91 per order compared to $121.34 for Android users, a difference of 4%.

Facebook vs. Pinterest: Shoppers referred from Facebook (FB) averaged $101.52 per order, versus Pinterest referrals, which drove $98.25 per order. Facebook referrals converted sales just slightly lower than that of Pinterest referrals.

The numbers could make up for the lower sales over the Thanksgiving weekend. Approximately 141 million shoppers made purchases over the four days ending Sunday. But consumers, on average, spent 4% less than they did last year, thanks to strong promotions and sales by retailers, the NRF said on Sunday. The NRF estimated that shoppers, on average, spent $407.02 compared to $423.55 last year. Total spending for the four days is expected to reach $57.4 billion.

Still, of those who shopped online over the weekend, the average person spent $177.67, or approximately 43.7% of their total weekend spending, up from 40.7% last year.

The growing percentage of online sales is also noted by comScore, which reported that online sales on Black Friday totaled $1.19 billion, up 15% from last year. Nov. 29 was the season's first $1 billion day as well as the heaviest online spending day to date. Thanksgiving Day online sales jumped 21% to $766 million, comScore said.

Online spending for the first 29 days of the November-December 2013 holiday season rose 3% to $20.6 billion, according to comScore.

Approximately 66.1 million Americans visited online retail sites on Black Friday via their computer, up 16% from a year ago. Not surprisingly, Amazon (AMZN) ranked as the most visited online retail site on Black Friday, followed by eBay (EBAY - Get Report), Wal-Mart (WMT - Get Report), Best Buy (BBY - Get Report) and Target (TGT - Get Report), respectively.

"Every year shoppers get more and more comfortable with buying larger items online which is driving online purchases higher," said Larry Chiagouris, a professor of marketing at Pace University's Lubin School of Business in New York.

Retailers are ready for the increased e-traffic. According to separately released data by the NRF's e-commerce division,, eight in 10 online retailers will offer specific Cyber Monday deals.

"Regardless of the exciting online promotions we've already seen, retailers are prepared to pull out all the stops for their Cyber Monday shoppers," Executive Director Vicki Cantrell said in a statement.

Written by Laurie Kulikowski in New York.

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