it depends on the hill shape and wind flow direction. the hill or any body of considerable volume reduces the area in which the wind can flow. by reducing the area, the wind must move faster to get through in the same amount of time. mountain tops tend to be windier because the deflected wind can't be directed into the ground, and thus gets directed upwards. But having said that, if you are standing at the bottom of the hill on the side facing the wind, you should experience an increase as the bottlenecking begins. If you are on the opposing side, you should experience a decrease. As for the sides, it just depends on the size of the hill. the wind will take the path of least resistance, a narrow hill, like a large thimble looking thing will have a lot of wind all around it, but less behind it, where drag streams will hide. a wide hill like a mountain range will see most of the deflection go over the top, and the sides really just depend on the width of the column of air.
But to complicate things further, flat land lacks the obstructions that deflect wind upwards so you spend a lot of the time experiencing uninterrupted wind. Whereas, hilly or mountainous regions will have a combination of accelerated as well as shielded regions, just depending on the geometries.
So, it can get pretty windy in Oklahoma, which is flat. But the windiest place in Oklahoma is standing right next to a large object. I hope that helps.