I looked at the GHCN Precipitation data. PRCP stations are not as prevalent, nor as old as the temperature stations so shorter time frame, since 1930, includes these stations:
The availability and reliability of this window appears useful:
There appears to be a weakly correlated increase in the number of days with any precipitation greater than zero:
As for categories of precipitation, there does appear to be a correlated increase in daily precipitation greater than 5cm. These events are not frequent.
There does not appear to be any significant change in the extreme precipitation events of daily precipitation greater than 15, 20, or 30 cm.