Over in my thread about ring-tile card, @flowdihow asked about a weather panel I included in a sample dashboard.
It’s just a bunch of card_mod styling applied to the inbuilt weather forecast card.
If you’re interested, I’ve written up how I did it on GitHub, where I also provide the background images for you to download.
Having said that, I just noticed a post on the amazing weather-forecast-extended card by @Thyraz. I haven’t seen it before - I suspect it is a much better option!