fair–weath·er 
/ˈfeɚˌwɛðɚ/ adjective
always used before a noun /ˈfeɚˌwɛðɚ/ adjective disapproving : loyal or helpful only during times of success and happiness
▪ They are fair-weather friends. [=they are friends when you are successful but not when you fail] ▪ fair-weather fans
▪ They are fair-weather friends. [=they are friends when you are successful but not when you fail] ▪ fair-weather fans
