Lauren, of Highland Park School, asks :-

How big is a raindrop?

Gavin Fisher, a meteorological physicist with the National Institute of Water and Atmosphere, responded:-

Raindrops come in all sizes from about half a millimetre to about 3 mm in diameter.

If they are any smaller they are really still cloud droplets, and are not big enough to fall out of the clouds. Rain forms when the droplets (or ice particles) in clouds either grow by themselves, or bump into each other, until they are big enough to fall.

Rain drops can sometimes be bigger. In tropical Islands such as Hawaii they can sometimes get up to 5 or 6 mm, thats quite a splash. Raindrops do not get any bigger than this, because they simply fall apart. You could do a little experiment on this. Use an eye dropper to make individual drops and let them fall from a building. See how big you can get them before they start breaking up on the way down. A fall of a couple of storeys high will do.

The average size of raindrops that we get in New Zealand in summer showers is about 1 to 1.5 mm in diameter. Rain in winter is more usually drizzle, and these drops will be 0.5 to 1 mm.

Hailstones can grow much bigger, up to the size of a golf ball or even an orange, because of the way hail forms in big thunderstorms and the fact that ice doesn't fall apart when it falls.