You are doing what you need to do...learn from the birds. If they all but shut when it's rainy, so should you! I practice the "less is more" method when it comes to calling all the time anyway, but especially if it's rainy. When it gets like this, they do tend, as previously mentioned, to stay on roost longer. They also, from my experience, do stay in more protected areas, and areas with good visibility. This can make them difficult to kill, because they can see you if you try to sneak in on them. I have had great success on rainy days finding birds in big, open fields and then waiting maybe 20-30 yards back into the woods in the direction I believe they will go to roost. You must be extremely careful getting into that location...hands and knees only and slowly. If you get in the right spot, it is only a matter of time before they come by. Take your pick and put him down. Never touch the call...they will come right to you if you are in the right location. Now, if you pick the wrong spot, and they start going the other way, try to call softly at them a bit. I have found birds to be just about as responsive to calls late in the afternoon as in early morning. Wanting to roost up with hens so they will be ready to be on them the next morning, perhaps. If they start leaving the field in a direction other than where you are, call at them a bit and you may well bring them right to you. Just don't try this too early. Be certain they are leaving. There are no two hunts that play out exactly the same, and like the old saying goes, there are a hundred ways to skin a cat. Keep learning from the birds and you will be successful. Study them. See what they do. Watch how they react to things. It will help you avoid continued mistakes, and add a few tricks to your bag.
I have yet to have a year that I didn't tag out on birds. I by no means contribute this to the idea that I am a master turkey hunter. I know that is far from the truth. But I do pay attention to how the birds act. What I do contribute the past success I have had to is this: 50% having decent places to hunt, 50% being in the right place at the right time and the last 50%, a little bit of lady luck. That's right...it takes 150% of things going right to kill some of these deceptive old gobblers. Now watch me kill ZERO birds this year!
They are willing to teach us how to hunt them, but too often we are unwilling to learn.