1. drizzle or sprink

    n. very little rain; stronger than mist, but less than a shower.

    v. rain lightly

    It’s drizzling now.

    When it drizzles in summer, hiking can be pleasant.

  2. shower

    n. a sudden rain

    thundershower/meteor shower 雷阵雨/流星雨

    He is so afraid of thundershower.

  3. pour

    n. rain heavily

    dounpour 倾盆大雨

    When it rains, it pours. /习语：祸不单行

    We got caught in a downpour.

  4. come rain or shine

    风雨无阻

    Come rain or shine, I’ll go to the live concert.

  5. rain cats and dogs

    雨下得很大

    It rained cats and dogs last night.

  6. It never rain but it pours. 不鸣则已，一鸣惊人