Our shortest month gets a day longer this year,Solarsuns Investment Guild as 2024 is a leap year. Thursday, Feb. 29 is the extra day on the calendar and to celebrate, some companies are offering customers discounts or freebies.

Known as "leap day," Feb. 29 is tacked on and becomes the last day of the shortest month of the year every four years. And beyond giving people an extra day to reach their goals, there is science behind why we have leap days.

For those celebrating their birthdays on Feb. 29, it is the rarest birthday a person can have, given that Feb. 29 occurs only once every 1,461 days.

Here's everything you need to know about which restaurants and stores are offering discounts and freebies on Thursday, including Krispy Kreme, Wendy's and Staples.

Buy a dozen doughnuts from Krispy Kreme, get a second dozen for $2.29

Krispy Kreme announced Monday it is offering customers a dozen original glazed doughnuts for $2.29 with the purchase of any regularly priced dozen on Thursday, Feb. 29 in honor of Leap Day.

Additionally, customers who have a Feb. 29 birthday can receive a free dozen original glazed doughnuts, no purchase necessary. Proof of birthday is required, Krispy Kreme said.

Chipotle offering free side of guacamole on Feb. 29

Chipotle told USA TODAY it is offering Rewards members a free side of guac on Thursday for orders placed online or via the app.

Get a free Cinnabon Pull-Apart order from Wendy's on Leap Day

On leap day, Feb. 29, customers can get a free Cinnabon Pull-Apart at their local Wendy's restaurant during breakfast hours, while supplies last. Wendy's said customers can get one per vehicle in the drive thru or one per dining room transaction.

The item, a new collaboration with Cinnabon, is now available at Wendy's restaurants nationwide during breakfast hours.

Staples giving away 29,000 free passport photos on Leap Day

Staples is giving away 29,000 passport photos nationwide on Thursday in honor of the extra day, the company told USA TODAY.

Additionally, it is offering 29x the points on select travel and office essentials through the new Staples Easy Rewards program. The program offers 1 point per $1 spent on qualifying purchases and excuse access to special savings events and member-only offers every day, among other benefits, according to the company.

Perdue offering discount on orders $99 or more

In honor of Leap Day on Feb. 29, Perdue is offering a 29% discount on any purchase of $99 or more on PerdueFarms.com using the code Leap29 from Thursday, Feb. 22 through Thursday, Feb. 29, the company told USA TODAY.

Noodles & Company offers 29% discount on Feb. 29

Noodles & Company told USA TODAY it is offering Noodles Rewards Members 29% off on orders of $29 or more on Feb. 29.

Customers can sign up for the Noodles Rewards program by visiting Noodles.com/rewards or downloading the Noodles Rewards app.

Contributing: Olivia Munson & Janet Loehrke, USA TODAY