Obviously what has to be answered is why do people perceive that
drizzle is wetter than heavy rain?

Could it do with the amount of raindrops per sq ft. Are there more rain
drops per sq ft in drizzle than heavy rain?


There are certainly many more drops per square foot, or per cubic metre
or whatever, in drizzle than in even quite heavy rain, which is why drizzle
reduces the visibility markedly. With rain, the visibility is only reduced
when it is almost torrential, and even some of that reduction may be due to the
formation of mist. The drops are much larger, and fall more quickly, but there
are fewer of them than in drizzle.

Tudor Hughes, Warlingham, Surrey.