In order for a plant disease to develop, the pathogen must be present, the host susceptible to that particular microorganism (and not resistant), AND the environmental conditions must be favorable for disease. Therefore, monitoring of weather data and its use in management decisions through models or simple decision aids has become important in integrated methods of plant disease control.
Here are links to some local public weather station networks:
Western Weather Group's Weather Data for the Lodi-Sacramento region (for historical data, under Weather Station Data click on Weather Database)
Additional, private weather station networks exist as well and can be located through your local pest control adviser.