dear all, i have note 5 and i have the same trouble so it leads me to here. but to no avail all the suggestions don't work.
eventually i long press the weather notification, just to find out that the weather notification that pops up at least 3 times a day is coming from google app.
how to disable it:
1. when the weather notification appear again, do not clear it. instead, long press until it opens up its detail.
2. you should be in "google app" now. at the top right, there is a cogwheel (setting obviously). click on it.
3. scroll down and you will find "Weather" option to be disable.
you might want to disable more than weather! I have just done it, not sure about its effect. but i am pretty confident that this will work!
p/s: sorry for the case insensitive. coming from a country that doesn't really care about grammar, spelling, and punctuation.