25 MPH will make me start looking at the UNDER
The wrinkle that has been thrown into the High wind/UNDER bets in recent years is coaches will forgo the field goal try from about the 15 to the 25 (too windy) and go for it on fourth down. Leading to more 7 point tries than 3 point tries. Damned if you do, damned if you don't.
To get a feel of the different wind conditions, drive your car with the window down, stick your hand out at 15mph, 20mph...30mph etc.
If you bet UNDER when the wind is 35mph or above you will have a long term winning pct above 53%.