Based on the fog and haze data from 8 meteorological stations in Wenzhou，the temporal and spatial climatic characteristics and the variation regularities of fog and haze days in recent 40 years are analyzed．The results indicate that from 1971 to 2008， the number of fog days in the urban area of Wenzhou significantly decreased． Fog days in exurban area of Wenzhou decreased slowly．Haze days in urban and exurban areas of Wenzhou increased from 1971 to 2008 as a whole， and such increase occurred mainly after 1979． During the period of 2001 to 2008， the number of haze days was the greatest in Wenzhou， with most fog and haze days in winter and least in summer． From 1971 to 2008， fog days decreased in most regions of Wenzhou， but haze days increased in all regions of Wenzhou， especially haze days increased rapidly in Urban. The relation has been found between fog， haze， precipitation， and API from the data of 2004 to 2009， based on which a forecasting model is established， with the forecasting accuracy up to 57% to 66%. The verification indicates that the relation is useful in fog and haze forecasting， and the computeraided automatic forecasting is applicable.