These days I go to windy.com for my weather nerd needs but it's quite different from Dark Sky.
I check it a couple times a day, and it's good enough for my needs. My bar's pretty low, though. The weather is rather unpredictable where I live; IME there's really no such thing as an accurate hourly forecast more than ~12 hours out. On Sunday night, today's forecast showed heavy rain and thunderstorms. Currently, it's 85 and there isn't a cloud in the sky. No amount of good dataviz can make up for that.
If you lived somewhere where you might take weather forecast accuracy for granted, I can see why you'd hate Samsung's app. It does the 24-hour hourly forecast and the 10-day daily summary just fine, but that's it. It'll show you current air quality and humidity, but no forecast data for those. Also, if you tap anything to see more details, it just launches an AccuWeather web page.