Abstract: Based on the meteorological data of 45 meteorological stations from 1954 to 2006 in the cotton production areas of Beijing-Tianjin-Hebei,the climatic characteristics of the continuous overcast and rainy during cotton growing period was analyzed.The results showed that the return periods of the continuous overcast and rainy were with 1-2.5 years,1-3 years,1-3 years and 3-5 years for the seeding,bud,boll formation and boll-open stage respectively,while the percentage of the continuous overcast and rainy accounted for 24%,39%,47% and 45% during these stages respectively.In the last 53 years,the variation tendency of the continuous overcast and rainy occurred was not obvious for seeding and bud stages,while both the continuous overcast and rainy and the serious continuous overcast and rainy occurred during the boll formation and boll-open stages decreased to a certain extent.The decreased occurrences of the continuous overcast and rainy during the late growing periods of the cotton were favorable to the improvement of the cotton yield and quality.

Key words: Continuous overcast and rainy, Continuous overcast and rainy, Climate characteristics, Cotton growing period, Beijing-Tianjin-Hebei Area