Originally Posted by crhptic
Darn, that's right, I forgot he was going in May. You are absolutely correct on the climate issue - I did that trip in mid-November, and while it was bearable (I would estimate in the 80-85 F range most days) I still felt hot. I'm used to wearing shorts and a t-shirt here in the States when the mercury is that high - the long sleeves and long pants thing was a bit rough!
Given the need to escape the heat at that time of year, my vote would change to a place I've never been but really, really want to visit: Sikkim. It's way off the beaten path, requires a special visa, hard to get to, and probably expensive to boot, but I will find a way there someday!
Or for something more simple, yeah, stick to the earlier suggestion to fly to Delhi and head up into the hills...

But Rajasthan is pure desert, and I can imagine you'd roast there in May.
The OP did say that the heat wasn't an issue, but rain was.
I have to say though, I was in Delhi in May last year-- my first experience of the Delhi summer in eight years-- and it wasn't all that bad. Granted that I am originally from there and was only there for a week, some might say even lucked out weather-wise, but prepared as I was to face the worst, I did not find the heat stifling.
Then again, when I lived there I really did love the Delhi summer.

Mangoes and long, lazy summer vacations-- what could be better!
But Sikkim sounds like a great suggestion. Never been there but have heard some good things about the local rum they brew in the North-east (amongst other things of course).
I also hear that Kashmir (Srinagar mostly) is again becoming a destination of choice for foreign tourists. Can't say how bright an idea that might be, but could be worth researching.
Best,