These gloves do a great job of keeping your hands warm on those 40-50 degree days.  I wouldn't give them a shot in freezing temps.  But in the late winter in central Japan they held up fine.  Their main feature is that they block the wind and keep some of your body heat in your hands.  After a few miles of running my hands got warm enough that I had to take them off.  They're also handy as an inner liner for any other gloves you have.

Buy them for running and use them as a glove liner as well.