31 Ọktoba bu ubochi nke 31st (nke iri atọ na out) na onwa ana kpo Ọktoba. Na Gregorian calender, 31 Ọktoba bu ubochi nke 304th (305th na afo nke ana-kpo leap year) na afo. Anyi nwere agugu ubochi 61 du mgbe afo na agwu.