Dōnglìng shíjié, běifāng de hémiàn dōu jié le bīng.
In the winter season, the rivers in the north freeze over.
Tips
usage
A written word; 令 here means 'season', as in 夏令. It lives mostly in compounds: 冬令营 'winter camp', 冬令时 'winter time', the standard time after the clocks go back, and 冬令进补 'taking tonics in winter'.