I often see fruits coloring up early, when small or immature, if they're under stress from insects or weather or disease. I get a lot of late PC damage on my plums, and they drop like rain, barely larger than the pits, but colored.

Today I saw a melon, not yet netted, on a vine dying of bacterial wilt, turning color. One of my apple trees that's been very stressed in the drought, has pingpong ball sized fruits with seeds already turning dark.

It's been such a stressed year, I think a lot of this is going on.

Thanks Itilton. I think the hot weather has had to do with a lot of stress on the trees. I am really shocked that none of my fruit this year if full-sized. Only a few peaches look as if they will swell a bit more. Is fertilizing a good idea at this time of year? Where I live in RI we have missed every huge rain/thunderstorm that has been on the news. They all moved north, south or out to sea before sharing one drop. Ugh

Its weird. Even around here in so cal. Usually the tons of neighborhood peach/plum trees all have pretty nice sized peaches on them by now but very few have them if any. The ones that do have peaches or plums are very small.

Yes, I had a pretty good load this year on a plum tree, and all dropped during the hot dry weather. I think when the trees are under heat and water stress, they will drop fruit to survive.