Stocks rose on Monday to start the annual Santa Claus rally--the final five trading days of the current year and the first two of the new year--as investors continue to weigh the risks the Omicron variant poses on Wall Street. The S&P 500 closed at a fresh all-time high, while the Dow Jones Industrial Average rose over 350 points and the Nasdaq climbed over 1%.

Here's how the market settled to start the week:

S&P 500 Index (SPY  ): +1.39% or +65.55 points to 4,791.34

Dow Jones Industrial Average (DIA  ): +0.98% or +352.21 points to 36,302.77

Nasdaq Composite Index (QQQ  ): +1.39% or +217.89 points to 15,871.26

Omicron, winter storm disrupt flight schedules over busy holiday weekend:

Airlines delayed or canceled more than 2,800 flights over the Christmas holiday weekend, according to Bloomberg, as the rapidly spreading Omicron COVID variant and winter storms disrupted flight schedules.

Carriers including United Airlines (UAL  ), Delta Airlines (DAL  ), American Airlines (AAL  ) and JetBlue (JBLU  ) all cited Omicron infections among crew members as the reason behind flight cancellations, as well as a major winter storm in the Northwestern part of the country causing delays on Sunday.

The year-end holiday travel period often includes some of the busiest days of the year. The Transportation Security Administration screened 13.6 million passengers over the last week through Sunday, according to TSA data, which was nearly double the number of travelers screened last year.

Holiday spending increased throughout the year's season:

Holiday spending rose 8.5% year-over-year this holiday season, which ran from Nov. 1 through Dec. 24, according to Mastercard SpendingPulse. Moreover, online sales grew 11.0% compared to the same period last year, preliminary data shows.

"Shoppers were eager to secure their gifts ahead of the retail rush, with conversations surrounding supply chain and labor supply issues sending consumers online and to stores in droves," said Steve Sadove, senior advisory for Mastercard, in a press statement. "Consumers splurged throughout the season, with apparel and department stores experiencing strong growth as shoppers sought to put their best dressed foot forward."

The spending gain was slightly less than the 8.8% increase that Mastercard (MA  ) has predicted, but was still the biggest annual increase in 17 years. Mastercard SpendingPulse measures in-store and online retail sales across all forms of payment, excluding automotive sales.

Here's how market benchmarks started trading soon after opening bell:

S&P 500 Index: +0.24% or +11.51 points to 4,737.30

Dow Jones Industrial Average: +0.17% or +61.77 points to 36,012.33

Nasdaq Composite Index: +0.85% or +131.47 points to 15,653.37