The State Climate Office of North Carolina posted a blog this morning describing some potential problems they were having with relative humidity sensors on their automated weather network.  The sensors were reading values much lower than is usually seen, and they were concerned that the observations might be bad.  The blog describes what they did to determine if the values were correct.  Quality control of climate records is an important step in making sure our measurements are accurate, especially when used for historical studies like changes in climate.  You can read the blog at

mtn_low_rh 12-4-2014