February 29th, 2020
Leap Days are needed to keep our calendar in alignment with the Earth's revolutions around the Sun. It takes the Earth approximately 365.242199 days (a tropical year) to circle once around the Sun. If we didn't add a day on February 29 nearly every 4 years, we would lose almost six hours every year. After only 100 years, our calendar would be off by approximately 24 days in relation to the seasons. The last leap year took place in 2020
Source: www.timeanddate.com/date/leap-day.html
