Hello, cant find this anywhere. Only says what date it ends but not time. So whats the time that sale ends?

It´s in the summer sale thread itself included:

"The Summer Sale ends on June 15th, 1 PM UTC."

https://www.gog.com/forum/general/summer_sale_on_gogcom_explore_a_galaxy_full_of_games_39163/page1

Yeah im stupid, just saw it few mins after I posted this, can I delete this?

You can ask a "Blue" (Gog Stuff Member) if he is willing to delete your thread.
But why? Maybe this is helpful for others as well. :-)
But thats totally up to you.
Stay healthy. Cheers.

You can always delete or re-write your first post using the "edit" option if you want.