Heating of fruit shortened the fruit growth period and reduced final fruit size.
Response of Cell Division and Cell Expansion to Local Fruit Heating in Tomato Fruit
So the take home message to all growers.... Keep your fruit cool and away from direct sunlight after the cell expansion phase ends... Remedy, Cover it or enclose it completely as Chris Delaney did years ago..... Always have a fan blow fresh air over the fruit.... This drives transpiration from the fruit itself..... So it will become a stronger sink as it demands more nutrients from both the xylem & phloem..
JASHS September 2012 vol. 137 no. 5 294-301