Has anyone ever had this problem? My Scosche Rhythm+ heart-rate monitor consistently seems to show my heart rate about 15 bpm lower than it should be. So, for example, on easy runs where I know by feel that my heart rate is about 140, it hovers around 125. And sprinting uphill, to try and push it to the max (my max being about 180), it won't go above 165.
I'm in London, where the temperature lately has been around 40 degrees F, is it just because of the cold weather?