Cada vez que + imperfect, afuera vs fuera
 

When cada vez que is followed by a past tense does it always have to be the imperfect?

If so is that because 'each time' is unspecific?

Eg. I wanted to go jogging, but everytime I looked outside it was raining.

Quería ir a trotar pero cada vez que miraba afuera estaba lloviendo.

Also with this same sentence is 'fuera' or 'afuera' slightly regional or would it have to be afuera because the act of looking is directional or expresses a kind of movement?

Thanks in advance for any insight that you can offer :)

Cada vez que enfrenté peligros lo hice con la cabeza en alto.
Y cada vez que hube terminado un examen, dormí una siesta en mi pupitre.

Common speech tend to use past simple/past simple and imperfect/imperfect, but that's not written in stone.

About

mirar afuera (where your sight is "pointing")
mirar fuera (the "place" you are looking)

Both are interchangeable almost always, and there are regional preferences. About your example, I prefer "cada vez que miraba fuera estaba lloviendo" because what is "fuera" is not a particular place but the opposite of indoors; but that is just an option.

You give such lovely answers, thank you :)