I'd probably be okay with that, but I don't like being uncomfortable. My girlfriend gets heat stroke when temperatures go over 25 degrees celsius, so that's a definite nope. Still want to visit Japan at some point though.
I find 25C fairly unpleasant and definitely "warm."
OSHA recommends offices to be cooled below that point, with 24C/76F being the upper end of acceptable. Some of this observation is also dependent on metabolic rate, which makes opinions on this somewhat gender-skewed.
