An outdoor heart rate monitor is designed for people engaged in outdoor sports and activities such as skiing, hiking, mountain biking, trail running etc. In such activities, knowledge of your altitude, of the changing weather pattern, and of your directional bearing can become quite important. A typical outdoor HRM therefore comes with an altimeter and a barometer. Sometimes it is also equipped with a compass.
Below is a compiled list of outdoor HRMs that have been featured on this web site. It is not an exhaustive list.
The simplest one is the X3HR unit. If you prefer something more advanced, then take a look at the X6HR or the T6. The Advizor has been around for quite a while now and is showing its age. The T6 and the X6HR use different PC software for planning and analysis. The T6 can be considered an advanced heart rate monitor with altimeter and other outdoor features. The X6HR can be considered an advanced outdoor wrist watch with heart rate monitoring facitilies. There are differences in their emphasis and abilities.