Blow hot and cold = react in different , unpredictable ways , so people are confused about how you really feel.

• He has been blowing hot and cold about the trip to Brazil.
• He keeps blowing hot and cold on the question of moving to the country.
• He blows hot and cold about this.  I wish he would make up his mind.

Get wind of something = hear about something secret.

• I don’t want my colleagues to get wind of the fact that I’m leaving.
• I don’t want the press to get wind of our plans at this stage.
• He got wind of the invasion in August 1942.

See how/which way the wind is blowing = to see how a situation develops before making up your mind about it ;  to know other people’s opinion.

• I think I will see which way the wind is blowing before I vote at the Board meeting.
• Those politicians know which way the wind is blowing among their voters.
• Sam failed to see how the wind was blowing and got himself caught up in an argument.