I think its by date so you could withdraw max at 11:59pm and then again at 00:01am two minutes later as long are both business days, may depend on individual bank card terms and conditions.
A warning, however, is that there are several security functions on ATM/Debit cards to protect you from identity theft. If you rarely use a card, and then suddenly begin maxing out the withdrawal limits, it gives the appearance of someone using a stolen card and the bank's security team may at least temporarily block your card for your protection.