Air temperature and relative humidity (T/RH) sensors (Onset Computer Corp. model U23-002) were measured from June 2015 to August 2016 at 100-m elevation intervals, from ~600 to ~1000 m, along a southeast-northwest trending ridge in the Luquillo Experimental Forest (LEF), eastern Puerto Rico. The prevailing wind direction is most frequently east to east-northeast and occasionally east-southeast so these locations are on the leeward side of the mountains; the data are within the timeframe and complementary to those collected at sites on the windward mountain slope. The T/RH sensors were installed with a custom-made PVC housing that had shade panels while allowing open air flow (Bassiouni et al., Fig. 2b). This housing was mounted on tree trunks 1.5-1.8 m above the ground. Air temperature and relative humidity data were downloaded every 2-3 months. Because air temperature and humidity were affected by site visits, data for one hour after downloading were excluded from the dataset. Reference: Bassiouni, M., Scholl, M. A., Torres-Sanchez, A. J., & Murphy, S. F. (2017). A method for quantifying cloud immersion in a tropical mountain forest using time-lapse photography. Agricultural and Forest Meteorology, 243, 100-112. doi:10.1016/j.agrformet.2017.04.010.