rain on parade

rain on (one's) parade

To ruin one's plans or dampen one's excitement. I hate to rain on your parade, but I think your A in chemistry was actually a clerical error. Mom really rained on our parade by chaperoning our school dance.
See also: on, parade, rain
Farlex Dictionary of Idioms.

rain on someone's parade

 and rain on someone or something
Fig. to spoil something for someone. I hate to rain on your parade, but your plans are all wrong. She really rained on our plans.
See also: on, parade, rain
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

rain on someone's parade, to

To spoil someone’s plans or celebration. This term, which calls up a vivid image of a downpour spoiling elaborate floats and dampening spirits, has been around since about 1900. Sheila Rule, reporting on a plan to replace Britain’s House of Lords with an elected second chamber, wrote, “But the opposition Labor Party, which has long sought to rain on the Lords’ political parade, is once again aiming at those men and women” (New York Times, 1990).
See also: on, rain
The Dictionary of Clichés by Christine Ammer
See also:
  • at (one's) doorstep
  • at doorstep
  • at fingertips
  • at one's fingertips
  • at (one's) fingertips
  • at your fingertips
  • at somebody's expense
  • at someone's expense
  • at expense
  • at (one's) expense