Would like to cancel subscription to weather

View, change, or cancel your subscriptions - Apple Support

No one here can cancel anything for you. You need to do that yourself. Read the above article for instructions.

In addition to what roaming gnome put, weather apps are notorious for installing profiles so you may want to check Settings>General>Profiles (if it's not there then there's no profile to remove) and delete the profile the weather app may have installed after cancelling your subscription.

We are fellow users, we can't do it for you, you have to do cancel its auto-renewal : View, change, or cancel your subscriptions - Apple Support