It was a leap year in 2020, so there was an extra day in the year compared to 2021 and the star sign dates were slightly different.
The star sign dates are calculated from the first day of Aries season, which is Spring Equinox.
Spring Equinox, the longest day of the year in the Northern Hemisphere, is a set moment in time every year where the Sun crosses the equator’s path and becomes positioned exactly above the equator between the Northern and Southern hemispheres.
Because of the leap year, this happens on a slightly different date from year to year.
That’s why Aries season sometimes starts on March 21 instead of March 20, pushing some of the star sign dates back too.
The next leap year isn’t until 2024, so we continue with the regular star sign dates for 2022.