Easiest way to display data (water temp of a lake) on a fenix 5 plus?

Hi there, I have no experience in building apps for Garmin watches but I have a simple usecase: My friends and I love Ice swimming and it is always interesting to know the water temperature in advance (neo or no neo - that is the question ;)). I scrape the number from an official website and can basically do with it what I want. What I haven't figured out is what would be the best way to display it on my watch. I read that watch faces can do background calls, but I am happy with my ActiFace, so I thought more of a widget like garmin weather. Or is there a way for some program running in the background and creating a custom data field? (Guess not). As the water temperature does not change that quickly an update once per day would be sufficient. 

Any ideas what would be a good approach? Thanks!