Ash Wednesday marks the first day of this penitential season in the Roman Rite of the Catholic Church and is always 46 days before Easter Sunday. It is a “movable” feast that is assigned a date in the calendar only after the date of Easter Sunday is calculated. According to the norms established by the Council of Nicaea (325 AD) and later adopted for Western Christianity at the Synod of Whitby, Easter Sunday falls each year on the first Sunday following the first full moon after the vernal equinox. This year the vernal equinox falls on Thursday, March 19, 2020 and the first full moon after that occurs on Tuesday, April 7, 2020. Therefore, Easter Sunday is celebrated this year on April 12. If you want Ash Wednesday, just count backwards 46 days and you get February 26, 2020.
But why 46? Why not the traditional 40 days? Short answer: the six Sundays in Lent are not considered part of the official “Lenten fast” (every Sunday is a special remembrance of the Resurrection of Christ), and so if you subtract six from 46, you get the famous 40 days of Lent. And so…Lent begins on February 26, 2020.