From Cumulus Wiki

Special Log for Temperature, Humidity, and Dew Point (inside and outside)

Steve Loft "Here's a facility which may be of some use, although it's limited" in the way I have implemented it.

If you stop Cumulus 1, and add a line to the [Station] section of the configuration file Cumulus.ini_(Cumulus_1)#Section:_Station:


It will then start updating a file called 'speciallog.txt' in the data folder with the following fields:

date(dd/mm/yy),time(hh:mm),inside temp,inside humidity,inside dewpoint,outside temp,outside humidity,outside dewpoint

The file just keeps on growing, it is updated at the same interval as the Standard log files and the Extra Sensor log file, but it is not specific to a particular month

This functionality is not available in Cumulus MX.