Comparison of Temperature and Humidity Data Measured at Cattle Farm in Japan With Meteorological Observation Records and NASA POWER Data.

To evaluate the utility of open-access meteorological observation records to estimate on-farm thermal information, temperature and humidity data during June 5, 2024-April 15, 2026 were collected on the Kyoto University Livestock Farm in Japan. Data loggers were installed in breeding barn, calf barn, and paddock. Daily average dry-bulb temperature (Tdb), relative humidity (RH), volumetric humidity (VH), and temperature-humidity index (THI) were measured. Ambient temperature and humidity were estimated using meteorological observations from the two nearest weather stations. NASA POWER daily average Tdb and RH data at the location of farm were downloaded. Correlations of on-farm data were 0.86-0.91 for RH and > 0.99 for Tdb, VH, and THI with estimated values from meteorological observations, while 0.73-0.74 for RH, 0.99 for VH, and > 0.99 for Tdb and THI with NASA POWER data. Downward biases for Tdb and THI and upward biases for RH and VH were observed and the degree of biases for humidity-related indices tended to be more pronounced during the cold season, while bias in RH was greater for NASA POWER data. Our results could provide novel insight into thermal information on cattle farms and using public databases to infer on-farm temperature and humidity.