Weather information has many applications in crop production practices, including disease forecasting. A variety of weather instruments are available for on-farm use, but associated costs and need for regular calibration and maintenance can limit actual use, especially by smaller growers. Subscription to an electronic meteorological service may be a viable alternative to on-site weather stations. In 1997 and 1998, hourly temperature, relative humidity and leaf wetness were monitored at six sites in a 400-m2 area of New Jersey with Field Monitor™ data loggers (Sensor Instruments, Inc.) and by subscription to SkyBit, Inc., an electronic meteorological service. There was close correspondence in temperature data from the two sources at all sites, the average seasonal difference ranging from 0 to 2 °F. Relative humidity data was variable between the two sources, the greatest variation occurring at low and high humidity, the ranges at which relative humidity sensors had been shown to be least accurate. Leaf wetness estimates from the two sources agreed at least two-thirds of the time. Data differences related to source were attributed to both systematic and random error. The usefulness of electronic weather data in crop production depends on how sensitive the particular weather-dependent applications (e.g., predictive disease and insect models) are to variation in the input data. The TOM-CAST early blight forecaster for tomatoes was not particularly sensitive to differences between SkyBit and Field Monitor leaf wetness estimates.