Heavy rain and feeling guilty about my bun in case he's bored!

Its terrible weather today and pouring down. Bun can either be in cage or out loose ( he has cover to sit under when out if he wants) but its so horrible and miserable.
I keep putting waterproofs on and going round to see him and give him a bit of food as a treat but I am getting much wetter than he is
I can't have another bun for all sorts of reasons and to be honest he has been much happier and healthier since his wife died ( we think he was very bullied) but on days like this I have a mega guilt trip

If he is an outside bun then he will be used to it as long as he has a shelter / hidey hole that he can go into of he wants.

I would recommend buying a large run with a roof. I would hate my rabbits to get wet (even if they did have shelter) so my rabbits have a 7ft x 5ft run with corrugated plastic on the roof and plastic on the sides of the run too. Even if its heavy rain, mine can still get to be outside and have a large space to run about in.