Final answer:
The best tool from the provided options to measure a change in precipitation is a barometer, but it's worth noting that a barometer measures atmospheric pressure, not precipitation.
Step-by-step explanation:
The best tool to measure a change in precipitation is not a thermometer, anemometer, or a barometer, but rather, it is typically a device called a rain gauge. However, from the provided options, the barometer would be the closest answer since it is related to atmospheric conditions, even though it measures atmospheric pressure rather than precipitation directly. A hygrometer could also be considered for measuring moisture in the air, but it is not one of the provided options. It is important to note that technically, none of the options listed are designed to measure changes in precipitation specifically. Nonetheless, a barometer and its function are well detailed in the information provided.