The average global temperature during the last ice age, which occurred about 20,000 years ago, was about 6 degrees Celsius (10.8 degrees Fahrenheit) colder than today. However, the temperature varied significantly from region to region. For example, in some parts of Siberia, the temperature was as low as -40 degrees Celsius (-40 degrees Fahrenheit), while in the tropics, the temperature was only a few degrees Celsius cooler than today.