Is there a clock that will help my mother know the difference between day and night?

Two clocks one painted bright yellow with the sun on it and another pained a dark color with the moon and stars.
the hospitalI was in last year had all the walls painted bright yellow and in some cases no windows. the rooms did have windows but many looked our of brick walls. If you did not have the window bed they kept the curtains round the bed pulled far enough so you could, actually see anything except your own dark corner. One day I took a long nap and when I woke up the clock said 3 o 'clock and i had to ask one of the nurses if it was night or day.

Good Lord! I remember this phase well! My mom would call me around 3:00am to ask me if it was am or pm. This happen regularly for over a year. I could never wrap my head around how it could not occur to her to look out a window to see if it was dark out. The first time she did it she was genuinely embarrassed and quickly apologized and hung up but after that her over-all confusion had taken over. I showed her the light marker on her bedside clock that indicated am/pm and also on her computer where the time stamp was - but none of that helped. Eventually, this phase passed but not before it had morphed into her calling me in a panic at 5am because I wasn't there yet to take her to her 11:00 doctors appointment! I finally found her a clock that was made for dementia patients. In large, clear letters it had the time, am or pm, day of the week and the complete date - no abbreviations for the days and months, it used complete words. Unfortunately, it was too late to really help but mom still liked the clock. And yes, it was spendy - about $100. I found it on Amazon.

You can find a "dementia clock" almost anywhere, including Walmart

There are specially designed Day Night clocks marketed at people with dementia and their caregivers. They cost a *mint*!!! - and for the adaptations they include, such as symbols showing a sun or a moon, or large AM / PM on the display, I thought they were pretty poor value.

In the end I plumped for a large, clear analogue wall clock that also showed the day, date and month in clear digits above, and has a white or black circle for am/pm. It still cost £100, mind you; and then mother had a stroke and developed a left sided sensory deficit which meant she could only see half the clock face anyway...

But, worth a try. Google "clocks for people living with dementia" to see what's available in your locality.