Time of use plans generally have lower rates starting late evening. There's no reason to run the dryer or dishwasher in the literal middle of the night. An hour before most people's bedtimes will still be during a lower tariff period.

According to https://www.energysage.com/electricity/whats-the-cheapest-ti... 9pm - 6am is common in the US. Hardly anyone is in bed by 9pm.

In the UK it's 10pm - 5am or midnight-7am, depending on your plan. https://uk.jackery.com/blogs/knowledge/when-is-off-peak-elec.... But there's also a mid-day slot 1pm-3pm which can work if your dryer can be timed.

You can also dry heavy items on a folding rack so the dryer doesn't run as long.