Often, humidity, air pressure, sunshine / cloud cover / wind / breeze, plus having to wear formal clothes especially tight collars and / or ties, or long trousers and long sleeves (think of Guards) etc are more important in how you perceive weather / atmospheric conditions than pure temperature. A bit like wind chill factor (combination of temperature and wind speed), but more of a comfort index. Could be any of those factors, and, depending on age and sex, menopause is also a possibility.