For a big tree to blow down and be uprooted by the wind it usually takes a wind speed of at least 85 MPH to blow over the big tree.
Of course if the rain is pouring along with the wind blowing then the rain saturating the ground can cause the tree to uproot with less wind speed.
I've seen some large trees blow over with the wind only blowing 65 MPH but it had been raining and down pouring rain for over a week during the time the tree got uprooted and blown over.
So if the ground is saturated enough then it can take less wind for the large tree to uproot.
I love trees for the shade but after having a big tree fall onto the back of my house during a storm I no longer keep any big trees near buildings or the house.
Because it can take very little wind to blow over a big tree if the rain is coming down and soaking the ground.
Now if it's just windy it's gonna take up to 85 MPH or 100 MPH wind to knock the big tree over unless the tree is rotted then it could take less wind to either break the tree or uproot the tree.