The success of the migration process, selection of breeding sites, and rearing of young for migratory birds is closely related to the timing of the spring migration. In our study, we used satellite tracking to analyze the factors affecting the timing of the spring migration of whooper swans (Cygnus cygnus) at wintering and stopover sites. The study aimed to understand the spring migration strategies of whooper swans and to identify important habitats for their conservation. In February and December 2015, sixty whooper swans wintering at the Sanmenxia wetland in Henan Province, China, were tagged with satellite transmitters. We determined the detailed timing of the spring migration at wintering and stopover sites and analyzed the correlation between the timing of the spring migration and climate factors. The results showed that the whooper swans wintering at the Sanmenxia wetland departed the wintering site from March 7 to March 8, and the departure date was significantly positively correlated with higher temperature and wind direction, but there was a significant negative correlation with wind speed. The whooper swans mainly migrated to the northwest from the wintering area, and the direction of migration had no significant correlation with wind direction and wind speed. The whooper swans generally departed the wintering site at night between 22:00 and 1:59, and they also started the spring migration downwind and during periods of low wind speed. The dates when the whooper swans were present in the stopover sites were mainly from late February to late March, and they tended to depart the stopover sites between 9:00 and 9:59. The proportion of whooper swans migrating in the day (52%) was slightly higher than at night (48%) during the spring migration, and the peak period of the whooper swan migration was from 6:00 to 12:59. The whooper swans mainly flew at night from the wintering to the first stopover sites, then during the day from the first stopover to the terminal sites. Higher temperatures at the wintering sites were beneficial for the growth of plants, which allowed the swans to rapidly accumulate energy reserves in advance of the migration. The field surveys indicated that human daytime activities such as fishing, farming, and grazing in the Yellow River valley, which contained important stopover sites for the spring migration, resulted in the swans foraging at night and flying during the day. To protect populations of whooper swans effectively, we suggest that existing threats to their stopover sites are addressed, including prohibiting development projects, building nature reserves, and improving public awareness.