Frost
coating or deposit of ice that may form in humid air in cold conditions, usually overnight
Is it common to see frost during some college commencements?
College commencement ceremonies often happen during the months of December, May, and sometimes June.  Frost isn't uncommon to see during the month of December, as it is the winter.
What seasons can you expect see frost? What months do college commencements occur? Do any of #2 occur during #1?