A large portion of my cherry tomatoes are cracking and splitting just before they get ripe.
How Do I Prevent Cherry Tomatoes From Spitting?
Certified GKH Gardening Expert
Temperatures fluctuating and uneven watering are common causes of tomato split. Much of that is out of a gardeners control.
You can harvest when they are slightly less then ripe and this can help with the crop.
Here is a link with more information.