elpenguino:

Err no, in leo they'll orbit the earth every 90 minutes.

 

Even so, when they are over your horizon, they're in shadow, for most of the night.  Surely every 90 minutes is irrelevant given how many there are, or will be.  However, LEO has to be low, and I imagine at high latitudes in summer, when the sun isn't far below the horizon, they'll be seen.