Without pictures it is hard to tell. But my first guess would be climate issues.I've picked 3 fruit so far. All off of hybrids. One had yellow/red and a few green areas. The yellow/ red spots can indicate disease. Especially if there is raised areas. But in this case it is nothing more that climate issues. Caused by the heat,wind, drought and possibly the hail stressed the plant enough that it contributed also. I picked the fruit and have it inside. It is evening up a lot although I doubt it ever will totally. Soil/fertilizer issues can contribute also. In your case I wouldn't worry. Nothing you can do much about now. And like BER I really doubt you will see it on later fruits if the weather moderates some. The last 4 years in the drought and heat I've seen some of it every year. Then as the temps moderate the ripening looks normal. All I do is pick them when I notice it and let them ripen inside. If the red section gets too soft then you might have to make a decision on eat the ripe section and either discard or fry the other section. My Mother would use the green section in chow chow ect if she had a few that way and was canning. Jay

I don't think it's disease because the tomato itself looks perfectly normal just bicolored. Well, if it's climate, there's not much I can do about it, I guess. It's not as much of a problem as the bugs. I have blister beetles, stink bugs, leaf-footed bugs and tomato fruitworm all doing damage to my tomatoes. I do bug patrol morning and evening and seem to finally be thinning them out.

Most of mine like that are caused by sunscald, and a few are caused by insect damage that isn't obvious at first. For me the sunscald is usually on the fruit facing west and with plants lacking leaf coverage.

Wasn't sunscald; I've had that too but only a bit as most of my tomatoes have an abundance of foliage. The green side was bright unripe tomato green and the red side bright ripe red. I didn't see evidence of insects although as I said, I've had plenty. This morning a plague of striped blister beetles. Hundreds of them on tomatoes and volunteer Amaranth. I dusted DE under the plants and then shook the cages to make them drop into it. Hope it kills them because if It doesn't the next dusting on the ground will be sevin and I really hate to use it.

When we had our 2 week stretch of 110-120 degree weather, my tomatoes did that and finally, just stopped ripening, altogether. Now that we've gotten back below 110, they're back to normal ripening again. I think I heard it has something to do with the enzymes that cause ripening not being able to function properly when it's too hot.

thanks, tracydr. That fits with Jay's climate idea. I brought them into the house and they evened up over a few days.

Mulbrerryknob,
I felt sure that they would even up some and that it was climate induced. I had never had much till the last 4 years of drought. The one I have on the table has evened up more than I expected. It has some scar damage from the wind beating it around in the cage. I've noticed when they happens many times I will see the yellow/red splotches. But they even up as they ripen if you pick them. I had one fruit that had some sunscald but not this one. This one was down low and had plenty of foliage cover. Sunscald looks different than what I have and what I feel you are seeing. Jay