Product review (5 stars): Great portable indoor Hygrometer that helps monitor Humidity and Temperatures.
I live on the coast, and use this in conjunction with a dehumidifier. The Hygrometer helps me know when the humidity is too high, or too low so I can adjust the use of the dehumidifier.

it is also handy for knowing if I'm having a hot flash, or if it really is hot indoors and I need to turn down the heater.