Btw. - and maybe this is mentioned somewhere in the twitter thread - the reason we add the extra day to February is because that used to be the last month of th

Btw. - and maybe this is mentioned somewhere in the twitter thread - the reason we add the extra day to February is because that used to be the last month of the year, hence months september, october, november, december having names that reference 7, 8, 9, 10.