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Is it possible to have rain without visible clouds?

As far as I know, clouds are liquid water and eventually the liquid water in them falls down, producing rain. Therefore one would expect clouds before rain.

But is it theoretically possible to have rain when there aren't any visible clouds? Maybe if the concentration of liquid water in the air isn't too high it is possible.

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I actually witnessed this in Ashland, OR several years ago. A strong winter storm had just passed when there was a sudden, brief downpour. When I looked up, there was not a cloud in the sky. What I believe happened is that the air was supersaturated with moisture when a brief breeze caused water to condensate around the few nuclei available. This seems to be confirmed by the second scenario in this explanation:

Consider the very rare situation in which still air is supersaturated with moisture (its relative humidity is above 100 percent) and clouds have not formed because condensation nuclei are practically nonexistent. Water vapor will quickly condense onto the few nuclei that are present and the droplets will rapidly grow into raindrops.

This is the one and only time I have ever experienced this.

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    $\begingroup$ can you put up a meteorological map for that day ? $\endgroup$ – gansub Jun 19 '16 at 6:04
  • $\begingroup$ @gansub, when I say "several years ago," I mean decades. This was in the late '70s (maybe early '80s). I doubt any weather maps are available for little 'ole Ashland from that day. $\endgroup$ – BillDOe Jun 19 '16 at 20:24
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    $\begingroup$ @BillOertell lib.noaa.gov/collections/imgdocmaps/daily_weather_maps.html $\endgroup$ – BarocliniCplusplus Jun 28 '17 at 15:52
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    $\begingroup$ @BarocliniCplusplus that's a good link. I've long searched for old DIFAX and stuff. Before the best option was just Iowa State's MTArchive. But that helps much, thanks! $\endgroup$ – JeopardyTempest Jun 30 '17 at 7:27
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Yes We have them all the time they are called sun showers Wind can push rain miles from the clouds that it falls from.

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    $\begingroup$ Always I've experienced sun showers, there were clouds. They were sun showers because there weren't clouds in the direction where the sun was, although there were clouds in the direction rain came from. As far as I can remember, I've always seen sun showers in the afternoon, when the sun low and clouds were high in the sky. $\endgroup$ – Pere Jun 28 '17 at 15:41
  • $\begingroup$ That's all anecdotal, sun showers only require wind and rain, there need not be any visible clouds, although there will usually clouds nearby, and of course clouds can dissipate while the rain is still falling, since it can take quite a while for rain to reach the ground in windy conditions. $\endgroup$ – John Nov 24 '17 at 4:21
  • $\begingroup$ Having recently experienced rain that was not falling from any clouds - on a very windy day - this agrees with my surmise that the wind separated and carried the rain away from the clouds where it formed (which may have dissipated). Scattered clouds were about but were entirely disconnected from the patches of watery "mist" - that look distinctly different to normal clouds, in the way that rain below clouds looks different to cloud. Technically, that may still be "cloud", but made of rain droplets. Different to "Serein"? $\endgroup$ – Ken Fabian Aug 29 at 3:02
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We have just experienced rain from an almost cloudless sky in Forster Australia at 1230pm Almost no wind at 4 knots. Humidity very high Lasted around 5 minutes with the rain drops increasing in size over the 5 minutes. Nickenter image description here

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  • $\begingroup$ There are clearly visible clouds here (not just the ones in the bottom left hand corner) so I'm not sure this really counts. $\endgroup$ – bon Jan 1 '18 at 8:51
  • $\begingroup$ Hi Bon, I intentionally included the little cloud as pictured, its not a rain cloud nor was it responsible for the shower. I have since learnt through the Bureau of Meterology that the phenomenon is a SEREIN which is a French name for rain falling from a cloudless sky. $\endgroup$ – Nick Minutillo Jan 1 '18 at 20:57
  • $\begingroup$ @bon - My observations of rain not falling from clouds were like this - the misty area is an aerial patch of water droplets (rain) held aloft by winds, that looks different to normal cloud. Technically still "cloud"? But different - the way that rain below clouds looks distinctly different to the clouds that it falls from. A difference would be apparent with the sun behind the observer - you would get rainbows from that rainy "mist" but not from the clouds at the bottom corner of the pic. $\endgroup$ – Ken Fabian Aug 29 at 3:10
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It is possible for a cloud to rain itself out. But it then takes some time for the rain to fall to the ground. By the time the rain reaches the ground, the cloud is no longer there. This is rare, but it can happen.

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This is absolutely possible, I was cycling my bike in a completely cloudless sky when I suddenly hit this wall of super humid and hot air. I had never experienced this kind of air before. As I passed into this wall of humid air, it started raining. I guess at 100% humidity, you only need a slight drop in temperature for the water to start falling out of the air.

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