Hi Matsu,
It may the type of water you have there or it may be as you said, you're not getting to dry the car quick enough before the water's drying.
You could try what Stealth said and rinsing each panel before you dry it, although, you may find that you end up getting the panels you've already dried, wet again.
We (especially on hot days) keep rinsing the car even while we're washing it, if that makes sense?
Jim washes the car with the shampoo and sheep puppet, and as he moves on to the next panel, I just keep rinsing where he's been with fresh water to make sure it doesn't dry out, that way, when we come to dry it off, it's still all completely wet. It'll be a bit of too-ing and fro-ing if you're washing the car on your own, but it might be worth trying that out to see if makes any difference?
Hope this helps