temper可以指脾气、性情，mood则不可以
This time, the policeman lost his temper. 这一次警察火了/发脾气了。
The boss is in a temper today. 老板今天脾气不好。
temper指心情、情绪时，与mood同义
That morning George was in a good mood/temper. 那天上午，乔治心情好。
但是bad mood与bad temper稍有区别:
bad temper是指a persisting angry mood(持续的愤怒情绪)：
When he is in a bad temper, he gets angry easily. But when he is in a bad mood, he likes to sit alone.
当他脾气不好时，他很容易生气。但当他心情不好时，他喜欢独自坐着。
mood可以表示有意/想要（做某事），temper则不可以
feel/be in the mood for表示想要做某事
At that time I was not in the mood for talking. 当时我不想说话。
