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[Turtle]

Originally Posted by Michaelangelica

Do plants make rain?

Plants contribute both water vapor & particulates, but more is necessary to have rain. I recall just the other day hearing a meteorologist say that all rain starts as snow, but before parroting it here I went checking. I found this most excellent & succint explanation, which speaks for itself.

source

Originally Posted by Paul

" Does rain start off as snow or hail and then melt on the way down?"

It most cases, yes. This is a process known as the Bergeron-Findeisen process. In most area's of the earth the clouds grow high enough to reach area's where the temperature is below the freezing point of water. Bergeron said that such clouds would contain both water droplets and ice crystals, and because water does not instantly freeze at 0 deg.C in may exist in a supercooled state.
The ice crystals and supercooled water coexist in the cloud with the water either evaporating or joining with the ice crystal to make a larger crystal, the more this happens the faster and heavier the crystal grows and the faster it ascends the cloud, eventually becoming snowflakes.
The falling ice crystals that are now snowflakes will melt and become rain if they encounter an air temperature on their way down that is = or + 4 deg. C

But not all rain starts off as snowflakes. In the tropical regions the clouds do not get as high, and as such are free from ice, they are "warm clouds". The rain here is produced by Langmuir's Chain Reaction, or more commonly the collission and coalescence process.
The water droplets collide and coalesce due to atmospheric turbulence and convection.

Here's a biographical piece on Langmuir: >> Irving Langmuir: Biography from Answers.com

An article on the Bergeron process: >> Bergeron process - Wikipedia, the free encyclopedia