I have two sinew backed bows I have kept around for myself. One is hickory and the other is osage. Both are 64" long, wide flat bows, and both are 50-55#'s. This is by NO MEANS a discredit to Pats observations, just my own add on's. I have never noticed either bow act or shoot differently in any weather I have had up here. If it was, it was so subtle I didnt notice it. I used TBIII glue on both, Im sure that plays a part.