I have built a weather clock using a Raspberry PI, a USB to Serial adapter and a second hand Point of Sale display.
When I started this project in 2014, I had just started working from home and I wanted an outdoor thermometer. Around this time, while shopping at a used book store, I noticed that they were selling their old Point of Sale equipment, having recently upgraded. So for $25, I bought one of the old POS displays to see what I could do with it. Also, I had been looking at the Raspberry Pi's and even though I was thinking "How cool!", I still couldn't figure out what to do with one. Having built the Current Weather PARFAIT API just a few years before, I realized that perhaps I could bring all of these things together into the Weather Clock. Since then, I have moved most of the logic to what is now the Weather API, vastly simplifying the code required in the clock itself. So much so, using a Raspberry Pi is definitely overkill.
Using Python3, I wrote 3 modules.
To have the clock run when the Raspberry Pi starts, I setup a systemd service pointing to POSClock.py. Instructions on how to do that can be found here.