Personally, I think that 'Home' weather Stations are a complete waste of money. However, they can be very interesting and often very decorative....I know because I had one which was never accurate.
As well as the hygrometer, you will more than probably have to regularly re-set the Barometer, especially if it is of the Aneroid type.
The following links may proof useful if you go ahead and get a 'Weather Station'.
http://exoticpets.about.com/od/herpresources/ss/hygrometer.htm
http://www.ehow.com/how_12172292_adjust-home-barometer.html
Hans.