I use an App called AccuWeather on my iPhone, and have always wondered what the 'dew point' number meant. I just looked it up on Wikipedia and discovered that while I still do not really understand what it means, I do know why I am feeling so cranky even though the temperature is only 27C and the humidity 88%. The dew point is at 25C. At the 24–26C dew point, according to the chart, it is "extremely uncomfortable, fairly oppressive."
This is not news to me. I knew it was extremely uncomfortable and fairly oppressive. But it is nice to have official confirmation of that fact.
(Four more days of work until the summer vacation arrives, but four more VERY BUSY days. And I have a cold, which doesn't help with the crankiness.)