+1 for Carrot. It's a one time $4.99 purchase and if memory serves me there is also a cost if you want to go premium which allows you to customize, get alerts and switch data sources between DarkSky and WeatherUnderground. I *think* that's an additional cost of $9.99 annually.
I had been using WeatherUnderground but I could not get it working with the infographic faces.
Another vote for Carrot. Try setting it in the sub-dial top and you can get snark on your screen.
I don’t have the paid version - that uses additional data sources that the developer has to pay for, therefore the cost. I am considering it though. You do get some other features like customization and notifications I believe, it isn’t a bad way to support the developer and it really isn’t a large amount. Subscriptions can also be cancelled.
Notifications are the only real attraction for me. If you’re only interested in notifications, you could just additionally buy Dark Sky, which includes notifications, and it’s a one-time buy at about half the price of a 1-year Carrot subscription.
I've come to like forecast bar. If you have series 4 it has a good complication for the infograph screen. Even if not, the complications are good, forecasts as good as any, and the iphone app very well thought out.
I do like all the info it gives me, even on the watch, when launched.