Two thirds of the country — an estimated 155.7 million people — are planning to shop “Super Saturday,” according to a National Retail Federation survey conducted with Prosper Insights & Analytics.

Super Saturday for many retailers is the biggest shopping day of the year.

The weather could be a big factor, with one to three inches of snow a possibility in major Northeast cities on Saturday. While temperatures in the New York area will rise to the 40s, snow is expected tonight into Saturday morning, changing to rain in the afternoon. Boston will be in the mid-30s, with a mix of snow and rain as well. Forecasts for Chicago call for Saturday to see snow and ice with the temperatures around 30 degrees.

Saturday’s wet weather could push a lot of retail business into Sunday, though rain and temperatures in the 50s is seen for Sunday in New York and Boston, while Chicago is expected to be sunny and much colder.

Irrespective of the weather, according to the NRF, 52 percent of Americans will shop for gifts online Super Saturday.

Forty-two percent of Americans will shop department stores; discount stores will attract 27 percent; clothing or accessories stores, 21 percent; electronics stores, 18 percent; local/small business, 14 percent, and grocery/supermarket stores, 13 percent, according to the NRF.

The survey polled 6,890 consumers from Dec. 1 to 7 and has a margin of error of plus or minus 1.2 percentage points.

“While many consumers got a head start with holiday shopping by taking advantage of extraordinary sales over Thanksgiving weekend, more shopping and great deals are yet to come,” NRF president and chief executive officer Matthew Shay said. “We expect retailers will once again be competitive on price and value options in the final stretch, especially on Super Saturday.”

The NRF said similar to previous years, only one in 10, or 24 million Americans, have finished their holiday shopping as of today. The average holiday shopper has completed 52.5 percent of their shopping, down from last year’s 53.5 percent.

“Even though there is still a lot of shopping left for the season, we are seeing Millennials continue the trend of an optimistic outlook heading into the final stretch,” said Prosper’s principal analyst Pam Goodfellow. “Although they tend to be most conservative holiday spenders, nearly half of those 18 to 24 say they are planning to spend ‘more’ this year compared to last, significantly higher than their older counterparts.”

As far as the kind of gifts consumers have purchased this season, the survey found 50 percent purchased clothing or clothing accessories; 36 percent toys; 34 percent gift cards/gift certificates; 33 percent books, CDs, DVDs, videos or video games, and 23 percent consumer electronics or computer-related accessories.

Experiences, such as tickets to sporting events or whitewater rafting are also popular gifts this year. The survey found that 23 percent of consumers are planning to give these types of gifts.

Although consumers are getting ready to complete their holiday within the next week, 48 percent of consumers are planning to take advantage of in-store after-Christmas sales, compared to 47 percent last year, and 44 percent are planning to shop online, up from 43 percent last year.