Like many folks, I try to combine trips to and from the office with other chores: stopping at the bank, picking up office supplies, etc. You know the drill. So, when I'm planning my day, I often visit the website of the store I want to shop at, to see what time they open. If the store opens later in the morning, I can plan my visit for later in the day.
If you don't tell me your store hours on your website, you risk losing my sale. I'll find someone else who's open and leave my money there.
Please remember your customers when you're planning your website or even if you just have a one-page placeholder (and not a full website). Give me, your customer, the info I need to make my decision. Your telephone number and your store hours are the bare essentials your customers will need and a good place to start.