To "see which way the wind blows/is blowing" is to observe a situation closely, so as to understand which direction it is heading towards or what is likely to happen in the future. Several different synonyms can be used to convey a similar meaning, such as "assess the situation," "gauge the mood," "read the signs," "determine the course," "evaluate the outcome," or "predict the future." The phrase can be used in various contexts, from politics to business and personal situations, to understand the potentials of an event or situation and make informed decisions based on the available factors. Understanding the signs or situation before making certain moves will help make informed decisions.