noun
coldest period; depth of winter
Refers to the coldest part of winter, often used in meteorological contexts or to describe severe winter conditions.
厳冬期には気温が氷点下まで下がる。
During the coldest period, temperatures drop below freezing.
登山は厳冬期を避けて計画したほうがいい。
It's better to plan your mountain climbing to avoid the depth of winter.
Compound of 厳 (gen, 'severe') + 冬 (tō, 'winter') + 期 (ki, 'period').