Hostility, harshness, or severity (of weather, climate, etc.); extremity of cold; (also) hardship or suffering caused by this. Also (later…

Austerity, severity, rigour, violence, especially of natural forces or features. Also: an instance of this.

Rigour or inclemency (of weather or climate); esp. extremity of cold.

With reference to the weather, landscape, etc.: harshness; ruggedness; bleakness.