  The COSINE-100 experiment is designed to test the DAMA experiment which
claimed an observation of a dark matter signal from an annual modulation in
their residual event rate. To measure the 1 %-level signal amplitude, it is
crucial to control and monitor nearly all environmental quantities that might
systematically mimic the signal. The environmental monitoring also helps ensure
a stable operation of the experiment. Here, we describe the design and
performance of the centralized environmental monitoring system for the
COSINE-100 experiment.
