Why Are There Only 28 Days in February?

Each month inِ the modern Gregorian calendar consists ofِ atِ least 28 days.
That number wouldِ beِ a nicely rounded 30 wereِ itِ not forِ February.
So whyِ isِ the mostِ widely usedِ calendar inِ the world soِ inconsistent inِ the lengths ofِ itsِ months.

The Gregorian calendar’s oldest ancestor, theِ firstِ Roman calendar, hadِ a glaring difference inِ structure fromِ its laterِ variants: itِ consisted ofِ 10 months ratherِ than 12.
In order toِ fully sync theِ calendar withِ theِ lunar year, theِ Roman king Numa Pompilius added January andِ February toِ theِ original 10 months.
When heِ reorganized theِ calendar’s dates toِ fit theِ newِ format, Numa triedِ toِ avoid havingِ months thatِ consisted ofِ anِ even number ofِ days, asِ Roman superstition held thatِ evenِ numbers wereِ unlucky.

Despite changesِ in theِ calendar asِ it wasِ altered afterِ Numa’s additions—alterations thatِ include theِ shortening ofِ February atِ certain intervals, theِ addition ofِ a leap month, andِ eventually theِ modern leap day—February’s 28-day length hasِ stuck.