It occurs in the same time frame, but not the exact same dates year after year. The Lunar New Year celebrations, in general, do not happen on the same day every single year either. It takes place between the months of January and February, but the exact celebration dates are dependent on the Lunar Calendar for that specific year. This year's Lunar New Year Celebration started on January 31st and commenced on February 15th of, 2022. However, in Overwatch, the event started earlier on January 25th and ran through February 15th. So, the game does try to match up with the actual holiday, but the dates are not always exact.