Polynyas play a crucial role in the polar marine ecosystem and climate system. Four winter polynya events north of Greenland have been observed, but their response to climate warming remains unknown. This study investigates projected changes in winter polynyas in the Wandel Sea north of Greenland using the AWI-CM3 climate model, which features 2-km ocean-ice resolution in the Arctic. We show that the model successfully simulates the main characteristics of observed polynyas. Future projections indicate that, under continued climate warming, winter polynyas will increase substantially in frequency, duration, and spatial extent once sea ice thickness falls below approximately 1.5 m. By 2100, polynyas could occur up to twice per winter, with a winter total duration exceeding 15 days under the SSP5-8.5 scenario. Our analysis indicates that sea ice thinning is likely the primary cause of these changes, as it reduces ice strength and enhances ice mobility.