Splitting is always a problem. Especially with heat extremes. It caused by inconsistent soil moisture levels - wet soil followed by dry and then by wet, etc. So the best bet is to adjust your watering pattern as much as possible and pick the fruit at blush (aka break stage) before watering.

Some varieties are more prone to splitting than others so what variety are you growing? Are your plants well mulched? How and how often do you water? Have you been pruning the plants at all? Can you shade the plants in any way from the late afternoon sun?

More info please.

Dave