To grow properly, tomatoes need a constant supply of moisture. If there is a sudden, heavy shower, the fruit may swell too quickly - causing these cracks. The risk is greatest (as in this case) with small fruit in relatively dry conditions that suddenly change.Inside, the fruit will be fine, but this weakness in the skin mean they will probably not keep more than a day or two so, if you can, use them quickly. Maybe a nice, hearty Bolognaise Sauce would be a good idea?
