On earth, it takes a "day" for it to rotate on its axis, and 365 of these days for it to revolve around the sun. On Mercury a "day" that encompasses a rotation represents 59 earth days, while it takes 88 earth days for it to revolve around the sun. This means that a "year" on Mercury is between 1-2 Mercury "days."
What might be the implications of this for Mercury? I am particularly interested in "weather" implications. On earth, a "weather" feature such as a "front" leading to a storm or a hurricane might take several days to unfold, while a climate change might take place over a quarter of a year (a season of 90 days). On the other hand, a "season" on Mercury might be 22 earth days, which is to say less than a 59 (earth) day rotation that represents a Mercury "day."