That's the problem with zone info, too general really. We usually plant out after May 12th here. No frosts after that, and I'm zone 6a. Since I grow my own I can plant out whenever and usually I plant out May 1st, sometimes I get hit though. I did this year, but the plants survived being hit by a frost. It set me back, but all have recovered now.
It's ideal here with temps between 75 and 83F. Great for flower pollination.
Many of my plants are now 3 feet tall, some I started later are smaller.
Black From Tula has been impressive. I have two plants both hit by frost, but now have about 5 larger tomatoes, and many more just forming.
Another impressive Plant is Stump The World
Black Ruffles had it's main leader frozen off and 4 branches formed and they are all loaded with fruit.
I had about 10 seeds of Carbon Copy cherry tomato. Only one germinated and it got hit by frost. I thought I lost any chance to grow this, but it somehow recovered! Yes!
This one is extremely hard to get, only gardeners have it, not for sale. Next year I will grow Carbon one of it's parents.
Bear Creek probably has the most tomatoes on it with about ten.
My dog is on watch for any critters thinking about bothering my plants. I got him trained now to go after birds besides tree rats. Jesse is the best dog I ever had. He's almost 5 now. I love him so much, he is family.
I used to start even earlier, but timing it so fruit forms in June is a great strategy here, as you pretty much eliminate BER, as the spring rains are done by June here. Which is the main cause in my area from being too wet. Even in containers, no BER if the fruit forms in June.