Technologies are generally described to monitor a sweat rate of an area of a skin. A hydration status of a human or non-human entity is monitored based on the sweat rate. The sweat rate is monitored when the sweat rate monitor is detected as sealed against the surface of the skin. The sweat rate monitor is attached to the surface of the skin with an adhesive, or a tape among other schemes to hold the sweat rate monitor in place during a measurement. The sweat rate monitor includes a container to capture an initial amount of sweat that comes out of the surface of the skin. When, the container is detected as filled with the initial amount of sweat, a pump of the sweat rate monitor is actuated to compress the container. The container is compressed to force a volume of the initial amount of sweat in the container out of an ejection port of the sweat rate monitor.