We observed behavior response of overwintering Aythya baeri to different weather conditions by using fixed point-based observation and scanning sampling methods, at Henan Minquan National Wetland Park during November to December 2018. The results showed that, on sunny days, the dominant behaviors of A. baeri were resting, flying, and locomotion (65.5%), the second were foraging and maintaining (31.9%). The daily behavioral rhythm was foraging in the morning, resting at noon, and foraging and maintain in the afternoon. The flying usually occurred before the peak of foraging. The locomotion behavior was mostly accompanied by other behaviors, which positively associated with foraging and negatively correlated with resting. A. baeri increased resting and foraging in rainy days compared with that in sunny days. The dominant behaviors were resting, foraging and locomotion (76.5%), and maintaining and flying were the secondary (20.3%). The peaks of foraging and resting postponed to the evening, while the flying and maintaining were significantly decreased. Compared with the sunny days, the resting, foraging, locomotion and maintaining behaviors were increased in mist days, and flying was decreased. The peak of foraging delayed to the noon and afternoon, and that of resting postponed to the afternoon. The dominant behaviors were resting, locomotion and foraging (70.6%), while maintaining and flying behavior were the secondary (27.5%). In summary, there are variations in time allocation of A. baeri behaviors, activity rhythm and dominant behaviors due to the change of weather conditions during wintering. To overcome the bad weather conditions in rainy and mist days, A. baeri would allocate more time on foraging for increasing energy intake, and more resting time for reducing energy consumption.