After looking into how average temperatures are calculated, I get “Average yearly temperature is calculated by averaging the minimum and maximum daily temperatures in the country, averaged for the years 1961–1990, based on gridded climatologies from the Climatic Research Unit elaborated in 2011.”
This means a country like France, that is mostly quite warm, but also has Mont Blanc, where it will be cold at the top, would look significantly cooler than it is.
After looking into how average temperatures are calculated, I get “Average yearly temperature is calculated by averaging the minimum and maximum daily temperatures in the country, averaged for the years 1961–1990, based on gridded climatologies from the Climatic Research Unit elaborated in 2011.”
This means a country like France, that is mostly quite warm, but also has Mont Blanc, where it will be cold at the top, would look significantly cooler than it is.
I think using the average temperature of the capital city is more useful, as this gives you the temperature in the place that the people are (https://en.wikipedia.org/wiki/List_of_cities_by_average_temperature)