The barometer/altimeter definitely have issues with accuracy. I have access to gov't certified barometers at work, and this watch is nowhere near. Even when recalibrating the watch to the known values, it tends to drift off quickly. The temperature function is useless except to measure water temperature when submerged or for ambient temperature when not worn for over a half hour, and then still not accurate. The tide charts are off by over an hour for my location. All of the default's are set to non-US standards. And the compass is off by about 45 degrees. I would not recommend this to anyone.