Simply, some plants do better when it’s not blazing hot. In extremely hot temperatures fall vegetables go to seed, called bolting. Or in the most of cases they get killed by temperatures that are too hot.
The benefit of planting a fall garden is that the soil is already warm, which encourages seed germination and root development. In general rainfall in fall is perfect for keeping treatment in seedlings and plants moist. However we recommend you to water if there’s no rain for a week or more.
In many ways fall gardening is similar to Spring in that you are always trying to out-guess mother nature. Dodging killing frosts and freezes is almost the same. Vegetables that thrive in fall season are cool season crops.