During the hot, humid summer months, meteorologists often discuss the heat index instead of the actual air temperature. But how is the heat index calculated, and why is it more important than the ...

The charts below show how observed highs and lows compare with average temperatures taken from data gathered from 1991 to 2020, which forecasters use to define climate normals that describe a ...

The planet’s average temperature shattered the previous September record by more than half a degree Celsius (0.9 degrees Fahrenheit), which is the largest monthly margin ever observed.