World War I broke out not long after Weyl took up the chair in Zürich. Being a German citizen he was conscripted into the German army in 1915 but the Swiss government made a special request that he be allowed to return to his chair in Zürich which was granted in 1916.
Bilang isang Aleman na mamamayan siya ay conscripted sa German hukbo sa 1915 ngunit ang Swiss gobyerno na ginawa ng isang espesyal na kahilingan na siya ay pinahihintulutan upang bumalik sa kanyang upuan sa mga Zürich na kung saan ay ipinagkaloob sa 1916.