Analysis in the 70s and 80s variously suggested that high pressure, high temperature and low humidity were associated with positive emotions - basically, nice weather seemed to put people in a good mood.

BBC: Does sunshine make us happier?

In the meantime, Weather Channel has used a simpler measure, called "feels like, " to express temperature in a temperature-like number, taking into account wind chill at low temperatures and humidity at high temperatures.

WSJ: In the Forecast: New Ways to Measure the Temperature