The shopping wars are heating up this July as Dollar General and Walmart offer discounts ahead of Amazon's Prime Day

• Amazon Prime Day has competition from a list of other retailers, from Walmart to Dollar General.
• Some rivals are offering longer sales or starting their discounts ahead of Prime Day.
• It's a chance for other retailers to challenge Amazon's dominance, one analyst said.

What used to be one of the sleepiest times of year for retailers has turned into a major shopping event thanks to Amazon.

Amazon's Prime Day this year will last four days between July 8 and 11 — longer than it has run before, and the earliest that the sale has started.

A range of other retailers, from Dollar General to REI, are also offering sales that coincide with or start earlier than Prime Day.

Fourth-of-July sales for products, such as mattresses or seasonal items like lawnmowers and inflatable pools, have been around longer than Prime Day. Overall, though, early summer was historically a slow time for retail.

"July used to be the dog days of summer when people didn't spend that much," said Zak Stambor, senior analyst of retail and e-commerce at EMARKETER, which shares an owner with Business Insider.

Prime Day, which Amazon first hosted in 2015, changed that.

Now, "July is a time that consumers are conditioned to be on the hunt for deals," Stambor said. "Every retailer needs to respond and lean into that."

Best Buy, Dollar General, and other retailers are getting in on the action

Besides Prime Day, this year's sales lineup includes a seven-day Fourth of July sale from Best Buy. Like Amazon, Best Buy is offering deals on electronics to members of its paid loyalty programs. Best Buy's sale lasts three days longer than Prime Day, though. It also started on Monday, over a week ahead of Prime Day.

Dollar General is planning its own "7 Days of Savings" event, which starts on July 6. The dollar store's discounts for the sale are more limited than Amazon's, with one deal per day, such as a discount on a fan or a buy-one, get-one deal on bratwurst.

Walmart and Target, which have offered their own sales around Prime Day in years past, are also getting in on the action again. Walmart's sale, for example, will start on July 8 and run for six days. Members of Walmart+, the big box store's paid membership, will get early access to deals.

Department store Kohl's, outdoor gear retailer REI, and home improvement chain Lowe's are also among the stores offering Fourth-of-July and other sales around the same time as Prime Day this year.

Amazon may have drawn inspiration from its rivals for its longer Prime Day, Stambor said. Last year, when Prime Day was two days long, Walmart's sale was twice as long.

"Amazon can see that those events have resonated, and so why not hop in the pool and join them?" Stambor said.

All those deals could be welcome this year as consumers watch their spending closely and worry about prices going up due to tariffs. President Donald Trump's 90-day pause on many of the tariffs that he enacted in April expires on July 9, the second day of Prime Day.

Amazon still has an edge over many other retailers when it comes to conveniences like fast delivery and value, Stambor said. And marquee sales events like Prime Day allow Amazon to increase its market share in the long run.

Rival retailers' sales are also a chance for them to win over customers.

"What is their unique value proposition that will drive consumers to buy from them rather than just go to Amazon or Walmart?" Stambor said.