Well i got 3 small juniper about 5ir 6 inches tall. I need to repot em since the containers they came in are to small those little round ones. So after i repot them is it alright to put them back out cause my concern here is the temp is going to drop like from the high 60s to the low 30s and then back up. Will that hurt my plants?

Forgot to mention it will thunderstorm before the cold sets in.

Which part of the world are you in? Generally people avoid repotting at the start of winter, and repot in early spring. If you have cold winters the plant may not respond to tje repotting till spring making it susceptable to infections

So will it be ok to leave it in the very small container when i bury it for winter? It seems so cramped!

Is it unhealthy now? It IS in the small pot bnw isnt it?

Trees generally prefer to be routbound when in pots.

Its small like 3 or 3 and a half wide by 4 inches. And the plant is over 6 inches long or tall.

Trees are dormant in the winter. That means that they don't grow at all. It doesn't matter how small the pot is, as long as the plant is not active. I would leave it like it is and repot it in spring