The airfield where I work was closed until mid-morning due to fog. It never really cleared. I got a PIREP just after lunch (I do air/ground radio), giving 3 km vis. Not good enough for most PPLs, let alone a GFT! Grit your teeth and book your examiner for every possible day you can. The day before mine the wind was so strong I was doing stalling/slow flight over the same field for 30 min. The next day was as clear, bright and calm as you could possibly hope for.