Could I bring them outside during the day, to get the sunlight?
Yes, most definately...
Let them get used to the sunlight, the wind, the evening temps, and then even over night temps first before you stick
them straight in the ground...
*Think of yourself as the tomato plant..
Would you want to come from inside, heat controled,
no wind, and definately all tucked in warm and cozy
over night..
Then the next day, shoved into cold soil, hot sun baking you, windddd blowing you left and right, and you're like..
Heyyyyy whatt's going on?
And reallllly chilly/cold over nights???*
You'd be like, "Where's my momma??
So, go slow and let them get used to the outdoors
slowly..
I don't plant until around Memorial weekend..
Just to be on the safe side....