What determines the size of raindrops?

What determines the size of raindrops?

Several things; the first is the size and shape of the cloud. Flat clouds tend to produce much smaller raindrops than the tall, puffy Cumulus clouds (which, once they produce rain or thunder and lightning, are called Cumulo-Nimbus clouds). Second, the water content of the cloud and third, the amount of turbulence within the cloud. Turbulence slams little raindrops (or cloud droplets) into each other, building bigger raindrops.

By the way, raindrops .2 to .5 millimeters are called drizzle...those .5 to four millimeters are called raindrops. Bigger raindrops typically break up into two smaller raindrops.