I would say 40mph might be a little too much but if you really wanted to fly this is a good time to fly the "Trainer". My friend would tell ya, Only real pilots fly in windy days, and if you can fly on a windy day you can fly any day. Me personally I would say You made a good decision because its really not so fun to fly on a windy day (40mph winds) If it was about 20 to 25 I would say Fine but 40 is a little too much in my opinion and you will not enjoy flying that much.