[Analemma_]

The underlying data sources are not free, weather data providers charge per API request. Stock weather apps built into the OS eat this cost for you, but third-party apps can't do that, they either have to show ads (ugh) or have a subscription.

Of the $2.08/month this works out to, I don't know how much the devs have left for themselves after the weather API and Apple's 30% cut, but I can't imagine it's much. I don't think you're getting ripped off here.