I grow Better Boy tomatoes in Michigan. For an earlier tomato, I always grow Early Girl. If you don't need full-sized tomatoes, try cherry tomatoes. They will mature anywhere. All tomatoes like hot weather. If your summers are cool, these tomatoes will grow, but won't do as well. Try using black plastic and spread it on the ground around your tomatoes. This will keep the ground warmer.
There are some new varieties bred by the University of Minnesota. I'd search for these if you are in a really cool area.