apparently a thing now; we've had quite persistent rainfall over the last few days in Brighton and during this period I have witnessed four different people (all looked to be late 20s/early 30s, liberal, beard and glasses types) standing outside in the rain holding up a test tube with a small funnel attached to the opening.
One guy I saw on consecutive days in opposite ends of town doing the same thing, so I had to ask him. He said he was "collecting the rain". He said when he returns home he then "labels and archives" this rain before placing it in storage. His ultimate goal was to collect the rain from every county in the UK, but apparently some places have different rain in different parts of town, hence why he was collecting the rain twice in different arts of the town.
I didn't continue with my questioning as there is a chance he was taking the piss, but something is going on here.