GPS low sat count now for no reason

I am suddenly getting no or very low satellite counts (3 or 4 sometimes) on my Pixhawk. I changed my GPS but same result. It seemed to change over night for no reason.

Mission planner screen shot and set up parameters in attached pictures. The only problem I can see is GPS time is wrong.

COULD IT BE THE WEATHER? - it has been very overcast and damp here since the problem started.

Yes, either the weather or RF interference.