Why is it raining when there isn't a cloud in the sky??

Question

I live in the far northwest corner of Washington state, where today was a gorgeous, sunny, cloudless day. But I just looked outside and saw raindrops coming down! I went out and stood in the middle of the yard, and it is, in fact, raining IN SPITE OF THE FACT that there still is not a cloud in the sky for as far as I can see in every direction!! The sky is totally blue! To be sure, the rain is very light--unusally fine drops--but am I going nuts, or what?? This has been going on for half an hour! Is it possible that there are clouds so high up that I can't see them? This is just too weird!

Answer 1

transperant clouds, or a sprinkler nearby

Answer 2

Impossible! It must be night time and you can't spot the clouds. I've been studying meteorology for a long time and I have never seen rain without clouds. I can see it can rain when there is partial clear with mostly cloudy skies, now that is possible.

Answer 3

The only times when I had heard about people who reported steady light precipitation when there is not a single cloud in the sky is when they were located near a tall mountain or mountain range.  If your case, I think I know the answer.  

Looking at a topography map of the State of Washington and at the last visible satellite imagery, I can see that there are mountains to the your south that are still snow capped.  Then I looked at the weather balloon sounding taken early Sunday morning and it showed about 50 mph winds blowing from the southwest near the mountain top elevations to your south to southwest.  

Looking through the National Weather Service data...there were some mountain snow reported in your area recently. Putting all this together,  I think it is likely that the winds aloft are blowing the relatively new deposits of snow off the top of the mountain.  This wind will carry the snow to the north  and towards the northwest and northcentral part of your state.  As this snow falls back to the lower elevation, it will melt and become drops of water.  The air mass at elevatrion 5000 feet and below were not really very dry on Sunday based on the weather balloon data.  So that will allow a better chance that these water droplets make it all the way to near the lower elevation surface without completely evaporating away.  

My conclusion...your light precipitation is not from any rain cloud, but from melted snow that was being blown off the snow capped mountains to your south.  And you are not going nuts!  

There are documented cases of this happening before.  And I remember a spotter calling once before telling me it is snowing with no clouds.  After talking to her, we both came to the same conclusion that it was from the snow covered moutains near her house.

Answer 4

There has to be rainclouds somewhere near or it can be dark and you dont see them.

Answer 5

This is possible. It happens for two reasons. One, there are rain clouds in the vicinity of 10 to 15 kilometers. The rain begins to fall from a height of say three to four kilometers. Before it gets to the ground it is caught by a blast of cold wind which carries it over your house where you feel it is raining.

Two, the sky is clear but there is humidity in the air. There is a cold wind at a height of one to two kilometers and it condenses the humidity of the air into raindrops and you see rain falling for one hour or so.