I'm going to use an old analog clock and replace the numerals on the face with small screens that will display the weather that corresponds to that hour. I still haven't decided on the hardware, but it will probably be a Raspberry Pi as the brains to pull the weather information from the web. The screens aren't set in stone yet either, I'm thinking small cell phone style screens, but I have also been eyeing the E-ink development kit at Adafruit that includes a 2.7 inch e-ink display. I have to do more research to see if this is a viable option, but it would save energy for a display that's only going to be updated once every 12 hours.
This solves a common problem I usually have: checking the weather for the time I'm going to be out and dressing accordingly. I'm also an avid motorcyclist, and if the weather is going to be nice, I can save the environment a little by riding a motorcycle.