better boy tomatoes not turning color real fast

[Garden78]

Hi. I am growing better boy tomatoes in containers. I live in fredericksburg, va. Some of my tomatoes are turning but some are not. Also, some of my tomatoes are getting a little black on top of the tomato but it is not like blossom end rot. Could this be because of the weather or lack of fertilization or uneven watering or they just need more time to ripen? Any advice or help would be greatly appreciated.
Conor W.