A Very Humid Summer

Why was my basement dehumidifier still running in late October?

The summer of 2019 saw a high level of humidity sustained over four months, through the end of October!

2019 saw a large humidity range with average readings of 25% during the winter and nearly 55% over the summer, a delta of 30%, and a rapid rate-of-change from late winter to summer.

This year, 2020, the winter was not as dry with a low about 30% and a summer peak above 50%, but much of the time was spent closer to 45% for delta of 15%, half of the 2019 range!

This sensor is located on the first floor with the front door opening into this room which may explain some of the volatility in maximum daily RH values, the winter in particular.