Rain isn't teardrop shaped

Real shapes of rain drops instead of tear shaped drops

When forecasting rain – however rare in Greece or Turkey – it is important to realise that most people get taught that rain drops are shaped like tears by (university!) teachers that are actively perpetuating this urban myth.
Weather icons used throughout the media are illustrative of this widespread fallacy, just do a google image search.

Yet, physics both predicts and shows that rain isn't shaped like teardrops and indeed the real – that is round – shape can easily be photographed. 1, 2, 3, 4
Also note that a spherical raindrop is a prerequisite for rainbows to occur. With teardrop shaped rain we would be deprived of this colourful phenomenon.

Actual shapes of rain drops

Although the predominant shape of a raindrop is spherical there is actually an evolution in morphology while the drop grows by gathering tiny drops and accelerates downwards. First the headwind will flatten the underside and subsequently bisect the rotund drop.

How rain drops and their shapes evolve
  • 1 mm in size:
    The raindrop is nearly spherical
  • 2 mm in size:
    The underside is flattened as the drop grows and its speed increases
  • 3 mm in size:
    A depression occurs in the centre of the underside
  • >4.5 mm in size:
    The incurvation increases and nearly bisects the drop. Via a long bridge the two halves are still connected for a brief moment – “the headset”
  • <1 mm in size:
    The collapse of the bridge (and subsequent loss of water) yields two new small and perfectly round drops, and the whole process starts all over again for each new one.

Related pages

How to forecast showers
Meltemi forecasting
Wind chill