I've only had them down to 45 so far. They kept my legs adequately warm in the 10-15mph winds. I would trust them down to around 35-40 depending on wind speed since they kept me warm as promised and the chamois was comfortable for the 30-40mile rides I've used them on
Very comfortable fabric and fit. Softer than most bibtights I have tried and good for cold , dry conditions down to around 40 degrees. Solid chamois , no complaints.
I am 6 ft 170 lbs and the XL is perfect. Rode at 39degrees with just these and I was very comfortable. I really, really like them and the price is reasonable given how ridiculous bike gear pricing can be. I tried the Castelli bibs and their sizing is so off. I def recommend these!