From Longman Dictionary of Contemporary Englishmidwintermid‧win‧ter /ˌmɪdˈwɪntə◂ $ -ər/ noun [uncountable] MIDDLEthe middle of winter The mountains look beautiful in midwinter.
Examples from the Corpus
midwinter• The way the year is running we could have a drought at midwinter and snowdrops at harvest time.• They lay their eggs in midwinter, incubating their eggs and chicks through many blizzards.• They crossed the Great Smoky Mountains in midwinter.• They crossed the Great Smoky Mountains in midwinter.• It was, as has often been observed, a safe prediction that major operations would not take place in midwinter.• Great patches of woods can, at the height of summer, have no rnore leaves than in midwinter.• Although it was midwinter now, the glade was as freshly green as the birch woods are in early summer. 