I've wetsanded and buffed cars the following day without problems. But I normally end up going over them a few days afterwards.
What I've been doing lately is painting the car, then machine sand and wetsand the next day. Then the following day after that, I do the buffing.
This seems to work the best.
The clear I used is a high solids (Shop Line JC6700), so this tends to stay soft a bit, then gets very hard once it does hard.
So different clears will react to buffing it the next day.
Motorcycle parts - I normally use JC630 clear of House of Kolor UC-35 are not high solids clears. I normally wetsand and buff these the day after painting.
Sooooo in other words, I would do the wetsanding early the following day. Then do the buffing the day after that.
30 degrees Celsius equates to 86 degrees fahrenheit so I don't see a problem in doing the above.