Q.Starting Seed Inside
I am starting some vegetables inside. Tomato, peppers, squash,cucumbers, melons, asect inside. I plan on starting several spaced about 25 days apart to spread harvest out. My garage is heated to about 65 – 70 degrees. Does it hurt them to place them outside on sunny days when temps are in the 40’s and 50’s the back in at night when it gets into the 30’s.

Certified GKH Gardening Expert
I would go no lower than the 50's as some of those listed will not tolerate temperatures that low, as seedlings.
Here are some articles that will help:
https://www.gardeningknowhow.com/garden-how-to/propagation/seeds/seedlings-after-germination.htm