A light fog?
No, seriously, thefreedictionary.com says:
n.
1. The middle position or part; the center: in the midst of the desert.
2. A position of proximity to others: a stranger in our midst.
3. The condition of being surrounded or beset by something: in the midst of all of our problems.
4. A period of time approximately in the middle of a continuing condition or act: in the midst of the war.
prep.
Among; amid.