Sports Fans who only cheer for or pay attention to a team when they are winning. Usually likes to be on the winning side of the coin. Usually looked down upon by serious fans.
Tony: "I thought you were a Florida Fan?"
Rob: "I was last year but I think this year Alabama is winning and I have always kinda liked them a little better"
Tony: "I didn't know you were such Fairweather Johnson, you suck."
Someone who is with you when times are good but will bail or dump you. When times get tough but will get back with you when times get good again.
Evan and King are in a Fairweather Relationship King dumps Evan when they are having trouble or when things get to hard. And gets him back when things are smooth again.
Someone who poses as a friend when it suits them, but are shady or shonky at other times.
After Mat broke up with my friend, he would act extremely shady all the time, pretending to lose his phone, and pretending not to receive SMS's. At times there was even no toilet paper, or shit on the walls. He is a fairweather friend.