Certified GKH Gardening Expert
Temperature has a big effect on tomato ripening and patience is a virtue when it comes to this. The unusual weather this year has affected many crops; however, with a little time and patience, they will eventually begin to turn color and you will be able to enjoy them. If your tomatoes are getting quite large and you are afraid they will either die or you simply cannot wait, then you can ripen them yourself. Here is more info: https://www.gardeningknowhow.com/edible/vegetables/tomato/how-to-turn-green-tomatoes-red-how-to-store-tomatoes-in-the-fall.htm
I am assuming you want to ripen them once they are picked. You can keep them on a window sill in a sunny location.
But for an even faster way is to put them in a brown paper bag - just don't forget about them or you'll have fruit flies and a mess!
Hope this helps!