The CS215 is temperature and relative humidity sensor manufactured by Campbell Scientific Ltd. This probe uses a Swiss-made digital humidity and temperature element that provides good measurement accuracy and stability. The elements are based on CMOSens® technology, which have been tested for more than two years in Alpine conditions where they were shown to work to their specifications in extreme weather.

One major benefit of the CS215 is the ability to change the sensor element in the field. Each sensor element is individually calibrated so no further adjustment of the probe is required; simply changing the element returns the probe to factory calibration state for both temperature and humidity, allowing low-cost field recalibration without lengthy interruptions to data collection.