The FORD recommended 5W-20 is not available here, so my dealer has been using 5W-30 instead. I was wondering whether it could cause any problems in the long run. No issues can be noticed so far.
Weather conditions here are mild, with low 30s in winter and low 80s in summer on average.

 

If the dealer is doing the work, you should be okay. The difference is minor and the only negative is slightly lower gas mileage as the 5W-30 is a bit thicker.

 

I just changed my oil an hour ago, put in 5w-30 Mobil 1

 

You will be fine with 5-30. It will only be slightly thicker once it is warmed up, and will not cause an issue I'm sure.

 

depends how hard you drive, if it will do anything at all. I hear it makes your engine a slight bit sluggish when cold but when it warms up its better for winter protection for some reason. Cant remember why though

 

The first number (5) is its "resistance to flow" at a specified cold temperature, I think around 32 derees F.
The second number (20 or 30) is its resistance to flow at normal operating temperature. Under laboratory conditions, basically better fuel mileage with the 20 weight oil but I haven't read how much better. The lower the number, the better it will flow.