The day before yesterday, when I opened the hood of my car, I noticed some fluid on the top of the lower engine cover. I drove a few kilometers and found that the fluid had dried without leaving any trace. A few hours earlier, I had washed my car in an automatic car wash.
The same thing happened today, but I didn't wash the car; it rained overnight. Is it possible that the automatic car wash and the rainfall caused water to accumulate there?
Does this happen in your cars ?

 

I would suggest testing your theory by using a garden hose over the hood area and grille area. Then wipe away the water from the hood and surrounding areas, then see if there is water in the engine pan again.
If so you may have a bad hood to cowl seal or a bad hood to grille seal.

 

@M60A3Driver Thanks for the tip. I'll check that way when I'm at my parents' house.
It's been raining all day in my town today, so fluid (problably water) has collected in that spot again.

 

This happens on my car. I open the hood and there is fluid on the bottom cover. It's disconcerting. My car is also parked head first out of the drive way and sloping down. I think when it rains, the water is getting trapped there. I am thinking about putting in a drain hole.

 

@xintersecty Thank you for the feedback.