Seeing as this ' summer' weather is so wet, our GPs haven't been out in the run nearly as much as I'd like - the grass is sodden. Can they run on the patio? - I know their claws would be filed down a bit but that would be a good thing!
If it's a bit damp on the lawn, I sometimes put our run half on the lawn and half on the patio, so they can still nibble a bit if they want. I usually stick an old towel down on the patio to make it softer for them and I don't leave them out too long as if it's damp it'll make them cold.
If it's really wet, I put them on old towels in the kitchen.
Perfect description 70! I feel so guilty when ours don't get out to play in the fresh air, so faff about setting up a run on the patio, put boxes, hay, grass etc in to make it interesting and then the daft buggers popcorn about, wreck the place and then hide. For ages. They don't seem to mind the concrete but it's cobbley stuff with dandilions growing in the cracks. I set the run up in the kitchen/utility sometimes too.
My grass is damp in the morning but I want them to get out. I have a 'soft' patio so I put them out in the morning. They have one of those Apex runs so have a good sized end bit with flooring. They seem to run out the end squeak for food and then retreat. Just watch their feet as they are delicate.