It seems from my experience that it tends to rain more at night. why is that? sure it is colder at night — but what does that have to do with rain?
I searched and found an answer on Ask a Scientist by that I am not sure I agree with:
Some types of precipitation are diurnally affected, such as thunderstorms that result from surface heating. These storms usually form in the afternoon, and may extend well into the nighttime, before dissipating in the early morning. Other thunderstorms associated with frontal movements may occur at any time, when conditions are favorable.
The heavy rains you mention usually occur in California as a result of
storms moving onshore from the Pacific ocean. But time of day usually is not a factor in these precipitation events. These storms may seem to occur during the evening and night, because people tend to be at home more at those times, and are more aware of adverse weather conditions. During the daytime, when they are at work, these rain storms may be less noticed.
It seems it really does rain more at right (at least in California) and that I’d actually notice it more in the day (because I am awake and sit by a window).