I'm not saying that you can't learn anything new about God in a valley season; I'm saying that's not the time you should be thinking about learning.
This is what happens - too many build their faith on other things, on the words of others or the experiences of others or even just vague ideas about what they think faith means and who they think God might be. Then, when trouble comes, they go desperately searching for the first time to discover who He is, but by then, it's too late.
It's this bias that our brain has to see things the way that we think we're going to see them or the way that we think we understand them. It's confirmation bias, in some ways, but it's also "absolute dread bias" - that worst case scenario sort of thing that is really hard for us to let go of.
If you go looking for God in the valleys, you're going to find a lot of valley stories about God. You're going to find the curses and the plagues. You're going to hear more from Job's friends than from Job's heart. You're going to discover the things you fear about God and about yourself. You're going to open your Bible and find a way for your valley to mean that you are hopeless, God is angry with you, He doesn't really care that much, and He's not coming to help.
You're going to open your Bible, and you're going to find a works-based way out of your problem, where all you have to do is have a stronger faith or pray more or read your Bible more (which at this point is not very encouraging for you). You're going to think you have to repent, really repent, pray toward Jerusalem, bow on your knees, throw yourself on the mercy of God.
This is where so many get false images of God. They don't go looking to figure out who He is until they're already in the valley and need Him, so all the stories they read about Him take on the tone of where they are in their life right now. They don't get a complete picture of Him.
Then, they hear things like, "God is good" or "God is love," and they wonder how this can be. And it all feels like a lie. It all feels like a farce. They can't find the real God because they don't know Him, and down here in this place? All of those shadows just start dancing darkness all over everything.
That's what I mean when I say that the rough season is not the time to be learning new things about God, although I confess wholly with my heart that some of the best things I've come to know about God have come from experiencing them first hand in the dark seasons.
It's not the place where you discover God, but it's the place where you discover that He really is all the things you've put your confident assurance in. It's not the place where you find God, but it's the place where you know that He truly has found you (and that, actually, He never lost you in the first place). It's not the place where you form your ideas about God, but it's the place where the vague outlines you have come into sharper focus.
This is, of course, all an ideal, but I recognize that life isn't lived in ideals. Plenty of persons have found God in the valleys. But I would propose to you the notion that it's only because they already had some idea of looking before they got there. Even if it's something they would not have acknowledged before that moment.
So yes, you can learn something new about God here, but if you're waiting for a place like this to learn...I'm not sure you can have the kind of experience here that you need.