
What's the heaviest rainfall ever recorded in Los Angeles
The greatest rainfall recorded was 26.12 inches happened at Hoegees which is near Mt. Wilson in San Gabriel Mountains on January 23, 1943. Other source reported that it is equivalent to 70% of the average annual rainfall in just two days. Los Angeles is prone to heavy rainfall and they experience frequent rain in a year.
Luckily the average precipitation on the record is 15 inches per year. Thanks to the proper drainage and wells in Los Angeles flooding was never been a problem there even with the frequent rainfall, unlike in early years where many livestock and products have been destroyed by rainstorms.

