Spring is here! moving indoor ----> outdoor

So, I know there's some threads on this already...but I'm still unsure about my situation.
My indoor setup is doing great and I solely use bought seeds inside.
I've also been saving all my bag seeds for outdoor.

So I sprouted about 8 bag seeds who are all about a week old...
They've been in a window sill ;during the daylight hours
and I move them to a cabinet
with a crappy 65W Spot Gro-Light and a 14W 225 light (blue and red) grow panel at night.

The days are getting warmer, and I want these seedlings to go outside soon...
Obviously I will bring them inside for any threat of frost and maybe even some indoor light at night.
How warm does it have to be for me to keep them outside all day?

Is high 50's ok? 60's? or should I wait until we have consistent 70's?

Depends on where you live...I leave seedlings in till about the first of may...but I start hardening them off outside around 4/20..I'm in tennesse and seen frost hit last week of April plus too much rain is bad to...

what u wanna do is harden them b-4 u totally let them loose outdoors...meaning put them in a shaded area not full sunlight when they are out and bring them in at night regardless of the temps...do this for about 10-14 days so they get used 2 the change....not 2 fun 2 jump into a freezing ass pull better to ease ur way in for better comfort right?.?.? works same way dont wanna jus let them loose it may (sometimes get lucky and dont) shock them and stunt the for as good few days so like said jus ween them out instead of letrting them loose

and on my side of the world, it's autumn

Rrrg I wish it was still getting in the 50&60's in the day time here in California I like the winter and we didn't even really have one this year, got like .5inches of rain.