When I was a student I got so hacked off with the weather I used to book 2 lessons per day (Sat and Sun); 1 at 9am, the other at say 1pm. This meant I got to fly once a week around 75% of the time, twice a week around 50% of the time, and four times a week around 25% of the time. From start to finish took me just over 3 months.