The objective of this study was to evaluate and compare measurements and estimates from Davis and Campbell Scientific Instruments in two automatic weather stations. Integrity of meteorological data for estimates of evapotranspiration of reference crop (ETo) from both stations was also evaluated. The following meteorological data were evaluated: air temperature, air humidity, wind speed, precipitation, net radiation and global solar radiation. The Penman-Monteith reference method to estimate ETo was evaluated daily. The weather stations were set up in an experimental area of the Rural Engineering Department-FACV/ UNESP, in Jaboticabal, State of Sao Paulo. Data were collected daily and statistical analysis was performed using linear regression analysis. The integrity of meteorological data to estimate ETo was evaluated. The results of the study in the stations using linear regression analysis showed that daily estimates for ETo had acceptable differences. The technique which evaluates the integrity of meteorological data revealed that data of relative humidity from both stations and of precipitation using Campbell Instruments were not good.