Unless you’re cycling through water like this (above). Then keep going in my view 🙂 Rarely on my bicycle tours has it rained continuously. I think the worst day when it comes to rain = was when I was cycling to Ambleside from around the Kendal area, in the lake district. It was extremely heavy rainfall and it lasted all day. I kept having to change my socks – as they became soaking wet and unbearable. I’ve learnt now to bring extra pairs of socks if it’s expected to rain…
However, a bit of rain, even if it’s continuous never hurt anyone. At least for me when I when listen to music it doesn’t bother me too much. The rain can be quite refreshing. Also, it can clean your clothes that your wearing 🙂
But yes, if there are storms etc (I experienced a nasty one briefly after Hamburg, Germany). Then it can be sensible to stop cycling.
I’ve also cycled through lots of hail, in rural wales, it was fast moving therefore not too unbearable. But it’s a good idea to take shelter during one of these storms, as this potentially can be dangerous.