By Siddharth Cavale

(Reuters) - Sales and traffic at U.S. brick-and-mortar stores on Thanksgiving Day and Black Friday declined from last year, as stores offered discounts well beyond the weekend and more customers shopped online.

Internet sales rose in the double digits on both days, surpassing $3 billion for the first time on Black Friday, according to data released on Saturday.

Data from analytics firm RetailNext showed net sales at brick-and-mortar stores fell 5.0 percent over the two days, while the number of transactions fell 7.9 percent.

Preliminary data from retail research firm ShopperTrak showed that shopper visits to such stores fell a combined 1 percent during Thanksgiving and Black Friday when compared with the same days in 2015.

The data highlights the waning importance of Black Friday, which until a few years ago kicked off the holiday shopping season, as more retailers start discounting earlier in the month and opened their doors on Thanksgiving Day.

"We knew it (holiday season) was going to be off to a slow start," Shelley Kohan, vice president of retail consulting at RetailNext, said.

"The first couple of weeks with the election were a complete distracter from the normal course of business and...a warmer climate in November may have made the sales more stubborn," she said, adding that she saw sales picking up in December.

Net sales on Black Friday slid 10.4 percent for brick-and-mortar chains, according to RetailNext.

"Stores that opened on Thursday were not very busy on Black Friday,... and while the Thanksgiving Day opt-outs were busier on Black Friday, they didn't see the crowds they saw in previous years," NPD group's Chief Industry analyst Marshal Cohen said.

ONLINE SALES SHINE

Still, total holiday season sales are expected to jump 3.6 percent to $655.8 billion this year, according to the National Retail Federation, due to a tightening job market.

Unemployment rates hit their lowest in eight years in October and hourly wages this year saw their biggest increase since 2009, boosting consumers' confidence and spending.

Consumers are expected to spend $636 on average on holiday purchases this year, up 3 percent from their 2015 spending plans, according to NPD.

Thanksgiving and Black Friday online sales tracked by Adobe Digital Index were $5.27 billion, up 18 percent from a year earlier and higher than its prior estimate of $5.05 billion.

Black Friday sales rose 21.6 percent to $3.34 billion, with purchases made on mobile devices contributing more than $1 billion in revenue, both record sales for the day.

(Reporting by Siddharth Cavale in Bengaluru; Editing by Jonathan Oatis and Andrew Hay)