In short, it depends. Earlier, the cheaper and older versions of tents weren't waterproofed but nowadays most of the new tents are waterproofed and come with rain flys. Don't assume they do, the best way to check is to test it by pouring some water onto the rainfly/tent and if it runs off completely and doesn’t leave any water absorption marks then it’s waterproofed. These sprays are usually cheap, so the best thing to do is to buy them to keep your tent waterproofed. Check out all the best waterproof tent on the market