This is an important question for those who are wondering if tomatoes that are setting now have enough time to mature before frost.
The first 2 to 3 weeks after the new tomato forms, growth is slow with tomatoes reaching about the size of a golf ball for slicer type tomatoes. More rapid growth occurs for the next 3 to 6 weeks resulting in a tomato that is mature size but still green. It takes several more days for the tomato to reach the mature color. So, from flower to green, mature tomato can take from 5 to 9 weeks. Tomatoes picked at the green, mature stage are not ready to eat but will ripen inside with little to no loss in quality. Just a few more days will be required for the tomato to go from green mature to fully ripe regardless of whether it is ripened inside or on the vine. Cherry tomatoes will take less time to develop than slicers and weather certainly makes a difference. (Ward Upham)