I've flown my Big Stick .60 in winds up to and around 30+ MPH. ( I have a wind meter so I'm NOT overestimating. ).

Above that, only a steady wind is doable, and there is no way that I would even attempt to fly it @ 40 MPH.

At 40 MPH things feel like a gale.

Even at 30, it is almost impossible to keep the plane from weathervaning on the ground or even KEEPING it on the ground... but you CAN fly and land the plane with these velocities if the wind is along your runway.

I've purposely loaded mine down with 4000mAh NiMH batteries to make it penetrate high winds better.