Not happy at all!
He always slept really well outside and he still would far rather be outside than indoors. I cringe when I see rain on the weather forecast!
He had real difficulties to start with and I had to do a combination of pat/shh and pu/pd. This took a couple of weeks, then a week or so more before I could just put him in and walk out.
However, even though it was hassle to do the switch back to the cot, I wouldn't do it any different if I was doing it again, I think the fresh air was really good for him, it also made it easier when we were away because he didn't have a cot dependence for sleep.