There you see the value of in-situ testing.
Right off the bat my suggestion would be a pole with 24 RGB Power LEDs, one for every hour. All closed hours would glow dimly red, all open hours in a custom color for each business, with the current hour brightly lit. The pole can either be flush with the building facade or stick out into the street for visibility. It is very visible, informative and a relatively low-cost modern touchpoint for customers.
For larger businesses I see more value in interactive touchscreen kiosks outside the building providing all information in a coherent experience.