Which preposition to use with weekdays

in Occurrences 2%

Every weekday in the Place d'Armes, squads of conscripts are busily drilling, running hither and thither with unflagging energy, and the air resounds with the hoarse staccato cries of "Un! Deux!

with Occurrences 1%

But these are dreams till summer; meanwhile we should be most glad to see you for a lesser excursionsay, Sunday next, you and another, or if more, best on a weekday with a notice, but

Which preposition to use with  weekdays