Winter is coming in the northern hemisphere and traditionally it is time for colds and flu. This has raised fears that coronavirus will surge when the seasons change, possibly leading to a second wave of the disease that is even bigger than the first. However, predicting what a Covid winter will look like is complex and uncertainty reigns - there are reasons both to be worried and to be reassured.

Contributors: . Micaela Martinez, an Assistant Professor in the Department of Environmental Health Sciences at Columbia University . Katherine Wu, a health and science journalist with The New York Times . Judit Vall, a professor in health and labour economics at the University of Barcelona . Dominique Moisi, the author of The Geopolitics of Emotion.

(A man walks through a snowfall in Sarajevo, wearing a mask as protection against Covid-19. Credit Mustafa Ozturk / Getty Images)