In addition to needing a way of holding the device so that it can be seen, one needs a suitable clock app. Apple's "built-in" clock is not suitable to my uses as a nightstand clock, so I have had to look in the App Store. Phil has a nice analog clock app, but I prefer digital clocks with displays large enough that I can read them without by eyeglasses.
My choice for a clock app having a display large enough for me to see (device nearby), and not doing anything I don't like or want (displaying ads or weather updates during the night, as some do, for example):
_The Clocks_, by Meanterm, Inc.
<https://itunes.apple.com/app/id403684793>
• Nice enough digital display in a choice of color. (Analog, too.)
• Brightness level is controllable.
• Several features in addition to the usual things associated with a bedside alarm clock, including different alarm settings for every day of the week.
• Wake to alarm sound(s) or music (or, therefore, any sound you put onto the device). It also permits very gradual fade-in of the alarm sound, beginning at the thin edge of perceptibility. I very much like this.
• Free.
To prevent notifications for interrupting one's sleep, iOS 9 and later have a "Do not Disturb" setting that prevents both audible and on-screen alerts of any sort: no phone calls*, no text messages, no calendar alarms, no Reminders notifications.
* A _second_ call from a number, within three minutes, will get through--for emergencies.
So: Engage _Do not Disturb_, launch _Clocks_, plug into power**, and mount the device rotated to _landscape_ orientation to "embiggen" the digital time display.
** I don't use a charging stand, because they insist upon _portrait_ orientation; the display is too small for me to read.
I will never again re-set the time of a nightstand clock for the seasonal changes of _daylight saving time_ state. (Gradually, I am doing away with clocks that require this. My wristwatch doesn't need it, _Serenity_'s wall clock doesn't need it, and I have a desktop clock in the house that doesn't need it.)
Excellent!
Mark_