I just moved to a new property and in a new town here in Northern California. I live closer to an area with hills than say a valley.

I noticed that in the morning, my downspouts produce a lot of water some days. You can see the wetness on the cement. I know this is due to the morning dew and condensation, but I noticed tonight one of the downspouts was dripping water at night.

Is there something like Evening Dew too? It is colder this week where the night temperatures are around 49/50 degrees. Another thing is I notice that this is only happening with one of the downspouts at night. I have like 8 around the home, but only this one. Does this happen if there is a blockage? Reason I ask is this particular downspout has some tree branches and leaves above it but I checked it last week and didn't see anything blocking it.

 

It's likely from the dew. Dew doesn't have to wait until morning to form. It all has to do with temp and humidity. Occasionally you see dew shortly after dark. Areas with less wind will have more dew than where there is a breeze.

If your gutter/downspout was blocked, you'd likely know it after/during a rain shower. It would also dry up after a long period of no rain.

 

Here in NC we get dew very regularly at night. Whenever the temperature falls there is the possibility of dew but when humidity is low it can take a larger temp drop like early morning when the day is typically it's coldest. I think most people aren't out of doors much after dark and just don't notice it but come morning everything is wet for everyone to see on their way to work.