About this time of year in the Pacific Northwest people start planting their tomatoes. The weather will probably cooperate and not get too cold at night. I like to wait another week or so to transplant, letting them hang out outside during the day, then bringing them in at night until I'm certain there won't be a light frost. Even though the USDA has adjusted their plant hardiness map due to global climate change, I still wait a little longer. Better safe than sorry.
Once planted, it really doesn't hurt to put a hoop house over tomatoes in milder climates. This helps maximize the heat from whatever sunny weather the garden receives. If it's hot outside, I make sure to ventilate, because believe it or not if it is too hot pollen can be damaged- thus lowering yields.
I also make sure of one important thing- and this is key. I grow short season varieties because I live in an area with a short growing season. Tomatoes, like everything else, have an average "days to maturity". This is different for each variety. The days to maturity are when you can expect your harvest. But unlike some other crops where the days start when you get seed germination, for tomatoes the days to maturity are after you have transplanted. If you buy a tomato that is 75 days to maturity, that does not include time you or someone else grew the tomatoes indoors for 6-8 weeks.
Lastly, if you have a few tomatoes at the end of the season that didn't quite ripen, you can bring them indoors and they will continue to turn red if they are in a warm place. I have done this several times with great success. I just put them in an open cardboard box and put them on top of the fridge for a bit, checking them every day.
Happy Tomato Season!