fair-weather friend

Etymology
From +, drawing an analogy between good weather and trouble-free times.

Noun

 * 1)  One who is friendly, helpful, or available only when it is advantageous or convenient to be so.

Translations

 * Chinese:
 * Mandarin:
 * Finnish: hyvän sään ystävä
 * German:
 * Italian: amico per convenienza, amico di comdo
 * Latvian: draugs pie pilnas bļodas (friend by the full bowl)
 * Polish:
 * Portuguese:
 * Punjabi: ਫਸਲੀ ਬਟੇਰਾ
 * Russian: друг до пе́рвой беды́
 * Thai: เพื่อนกิน
 * Turkish: