May be a little cool yet in your zone for best results outside -
"Coleus being tropical in origin responds to warm temperatures. 65-Degree nights, 70-80 degree days for best development. Cooler night temps can be used but germination will slow considerably"

Coleus self-seed readily outdoors so you can go ahead and plant them now. They will germinate and grow on their schedule.

So I can just leave the pots outside on the south side and make sure they are moisted daily?

found out that I won't have a big coleus plant this year since I've started very late :(

v1rtu0s1ty: So I can just leave the pots outside on the south side and make sure they are moisted daily?

Yes, that is correct. v1rtu0s1ty: found out that I won't have a big coleus plant this year since I've started very late :(

They may be big by the end of the season but they will be small for the majority of your growing season.

For tender annuals like coleus, impatiens, etc., it is best to start them indoors under lights or a sunny window 8-10 weeks before last frost.

Thanks rokal! I sowed them in shoe boxes yesterday. The seeds are experiencing 36F right now. Hahaha! I'll post pics if I see sprouts! I remember seeing sprouts after 3 days.

I sowed in April 15th indoors and they did not sprout. Next year I am not going to buy caladiums and coleus.
I worked hard on caladium, planted indoor some outdoor and everyone of those bulbs turned mushy or soft and did not sprout! Indoor room temperature was kept 70 and also was in southfacing window... but had no luck... there are so many other native plants which would have done so well, I feel.
the experience of trying to bring tropical feel and look was so dominant that I tried... but sago palm died and another houseplant palm died and also ruined the patch of soil where I dumped its soil. So much for liking tropical... I am going to love the native ones !

Mine didn't work. The ones I sowed inside worked. I'm not sure why it doesn't like outside.

Remember not to cover the coleus seeds after sowing. Just press them into the moist, well lit soil. I believe they need exposure to the light to germinate.