hit-and-miss

(adjective) something that is intermittently good and bad

Example Sentences:

The weather in Vancouver is really hit-and-miss. It can be sunny and rainy in the same day?

A: Do you like your new teacher?
B: He’s really hit-and-miss. Sometimes we have great classes where we learn a lot, and other days we just sit and talk about our weekend.

From the Blogs:

J-Lo’s Look, Hit or Miss?

Media:

Similar idioms:

1. hit it off
2. homesick
3. near miss