Remember WiFi but don't autoconnect on iPhone? I have 2 WiFi networks I can connect to at home. There is one that I prefer but is not the strongest signal, so my iPhone will usually connect to the other network. 

On occasion I need to connect to that other WiFi, so I'd still like to be able to easily connect to that one when I need to (not that often). Because of this, the Forget Network option on the WiFi connection settings isn't really suitable as I'd have to reenter the password to connect each time.

How can I remember a specific WiFi connection without having the phone automatically connect to that network when it finds it? I still want to autoconnect to other networks as normal.
Forgive me if I'm missing the point of your question, but if you've connected to both SSIDs and your iPhone remembers them (and their passwords), then why wouldn't you just go to Settings > Wi-Fi to manually choose and connect to the network you want when you need to?

My point is, according to your question, you'd still like to be able to easily connect to that one when I need to (not that often), and wouldn't this approach achieve that? It's easy to do and since it's not something you need to do often, it's not cumbersome. Your iPhone will remember the password and once you've manually selected a network it'll remain connected to it while the signal is strong enough.